With 100,000+ apps in the App Store, we can find apps for a variety of uses, such as turning your iPod Touch/iPhone into a professional camera/photo editor (for iPhone), an external hard drive, a reference book, or a radio, yet productivity apps that integrate with Google services, which are free and which we can use without Wi-Fi are harder to find. Not every place we are in will have Wi-Fi, especially if we are on-the-go or commuting a lot. That’s when apps with offline capabilities come in handy.
Two productivity apps that come natively on the iPod Touch/iPhone can be used offline: Calendar and Mail. Updating the native Calendar app with an entry in your iPod Touch/iPhone and seeing the same updates on your GCal has been possible thanks to Google Sync, which also syncs your Contacts and Gmail from your Google Account. Since the Mail app downloads your Gmail messages, you can read them offline, and sync the read messages when you get a Wi-Fi signal.
Productivity, however, encompasses more than just using the e-mail and calendar functions. Some people may need task management apps, better note-taking systems, the ability to edit documents or read their feeds. Check these apps to help you stay productive on the road!

Note: Not all apps are completely usable offline, because for some, you have to gather and save your information when you’re on Wi-fi so you can enjoy it during offline mode.

TASKS

Reqall, version 3.1.2

One of the most full-featured task management (and memory jogging) apps offering exquisitely complete features on the free version (the Pro version has more advanced features for the power user, such as ability to add tasks by email, and to get your Shopping List texted to you), the Reqall [iTunes link, website] iDevice app conveniently has a Shopping List, in addition to a To-Do List and a Notes section (see the Notes apps below) to which you can easily add tasks in offline mode by pressing the “+” icon.
If you include a date when you’re adding a task, then you will also see it (in addition to the category of Shopping List or To-Do) in the Today, Soon, or Later lists in the Time tab, which is if you’re interested in seeing your tasks by dates, just like in a calendar. When you have a Wi-fi signal, the app will automatically sync to your Reqall account, so you can access your To-Dos, Shopping List and Notes on the web, IM, email, by phone (U.S., Canada and UK residents can call Reqall to add, be reminded of, or share tasks with their Reqall contacts), and even Blackberry.

Milpon (For Remember the Milk), version 2.2

Although Milpon [iTunes link] is a third party application (not developed by popular task management app, Remember the Milk), this app is a free alternative for RTM users with no Pro account (required to use the free, native RTM app). With Milpon, you can add tasks in offline mode to your Remember the Milk account by tapping the “+” sign and see them listed by due dates (Overview tab), categories of personal, study, work (List tab), and tags (Tag tab). When you have a Wi-fi signal, you can press on the Refresh icon to sync tasks.
Find more details and screenshots in Angelina’s article.

NOTES

Reqall, version 3.1.2

Reqall, also mentioned in the Tasks section of this article, has a spectacular Notes section where you can access your notes (that you might have added in the website or by phone, as previously mentioned) in full (regardless of whether you only have 2 or 30+) and even edit in offline mode. Your edits to existing notes will be synced the next opportunity your iPod encounters a Wi-fi signal while you have the app open.
Editing new, un-synced notes, however, isn’t possible till after you sync. Thus, either be as thorough as possible before you finish the new note, or copy and paste your words into a new note with your edits. To add a new note, just tap the “+” icon and start off with the word “note” (alternatively, you can also select Notes in the “In” tab to add it to the Notes collection). If you have an external 3.5mm iPod Touch microphone or a pair of earbuds with built-in microphone, you can also add notes by voice.
One more tip: Even though you can’t organize your notes, Reqall has a great, real-time search function that will find any notes you may have stashed in your account.

Evernote, version 3.2.1 [Requires Favoriting A Note While Online]

Evernote [iTunes link, website] is a multi-functional note-capturing tool that can accept your notes from a variety of sources, and help you a great deal in school. While offline, you can access the notes from your Evernote account and create new notes right from your iPod Touch, but if you want to edit your rich text notes (say, ones that contain more than one type of font), you only have the options of appending text to your note, which means you can’t edit the text present in your note before appending, unless you copy and paste the text from the unrevised note and add your edits to the new note. For plain text notes, you won’t have that problem and will be able to edit them (in the beginning, at the end, etc).
To access notes offline, you will have to Favorite a note (by tapping the star) when you’re still connected to a Wi-fi network. You can also add notes by voice again if you have an external 3.5mm iPod Touch microphone or one integrated with your earbuds.

Simplenote, version 2.51

Simplenote [iTunes link, website] has an incredibly clean app that works well for adding text notes. Creating an account through the app was easy and required no clicking of an email confirmation link. Right when there was a Wi-fi signal, the notes synced instantly (I was very surprised by the lack of waiting time) to your account so you can access your notes on SimpleNote’s web-based application, which has a similar look. Even when you’re not using the web app, you can still access all your notes right on your iPod in offline mode.

DOCUMENTS

Documents 2 Free By Savy Soda (Google Docs Viewer/Editor), version 2.0

GDocs viewing apps flow in the hundreds in the App Store, but one that allows editing GDocs for free and offline isn’t as easy to find. Documents 2 Free [iTunes link, website] is almost there, letting you download and view your documents and spreadsheets from your GDocs account, edit them and upload them to GDocs. Once you download though, viewing and editing can be done offline.
It seems too great for the price of $0, but be warned that you might have to rename your GDocs Word documents’ extensions to .txt and upload them to GDocs with that name because this app doesn’t seem to read (or create) .doc files. That’s my workaround for the sometimes-unviewable Word documents in the app. Besides editing your GDocs, this app will also let you create new text documents, spreadsheets (.csv) and even sounds (.wav), that you can upload to GDocs (yes, even sound files since GDocs now accepts any file).

Dropbox, version 1.0.1 [Requires Favoriting A File While Online]

Often-favorited file-syncing application, Dropbox [iTunes link, website] enables you to not only view your photos and videos, but also your documents (.rtf, .txt, .doc, .pdf, etc).
You’ll have to press the star to add documents to your Favorites, which is the collection of files you can view offline, just like in Evernote. While the concept of keeping synced files across devices is neat, especially for students, this app lacks certain basic functions, such as the ability to edit, among others.

READER

Stanza (E-Book Reader), version 2.0 [Requires Downloading While Online]

Save yourself from having to go to the library or the bookstore, because with the e-book reading app, Stanza [iTunes link, website], you will have access to the catalogs of free e-book sources (such as king of public domain books, Project Gutenberg) and bookstores.
If you’re not so sure about squinting at the small screen, try adjusting the font size (Stanza offers a lot of options so you can customize the look and layout of the book) or even the effects and tapping functions. Just download the free e-book (or paid e-book from the bookstores) from the catalog in the Get Books tab while you’re online and enjoy it anywhere, regardless of whether you’re connected or not! You can also transfer in e-books you have in your computer with Stanza Desktop application, available for PC and Mac.

Read It Later Free, version 2.0.1 [Requires Syncing While Online]

While Stanza saves e-books to your iPod/iPhone, the free version of Read It Later [iTunes link, website] saves web articles so you can view them offline. You do need an account if you want to view your saved articles on the web, and use the bookmarklet for your mobile Safari browser while online, that will help you save a webpage.
If you use Read It Later’s Firefox addon (which enables you to save webpages from your desktop browser), just open the app when you’re online so it will sync the saved webpages and you’ll be able to view those articles on your iPod later in offline mode.

NetNewsWire Free, version 2.0.2 [Requires Downloading While Online]

NetNewsWire Free [iTunes link, website] is a simple Google Reader app that downloads your feeds (this can take a while if you are like me and have lot of feeds and unread items) to your iPod/iPhone when you’re online.  Once the app is done downloading, you can read all your GReader feeds in offline mode (just not the pictures accompanying the feeds’ articles), and mark items as read. Next time your device encounters a Wi-Fi signal and you have this app open, your GReader account’s unread items will be synced.

MobileRSS – Free Google Reader, version 2.2 [Requires Downloading While Online]

NetNewsWire is great if you just want to read your feeds, but if you want to add notes to feed items, manage folders, share your items by email, Facebook or Twitter, give MobileRSS [iTunes link] a try. Like NetNewsWire, MobileRSS will also download your feed items from your GReader account while online so you can enjoy them offline with accompanying pictures! After you mark items as read while offline, you’ll be able to sync read items in your GReader account the next time you get Wi-Fi. See more of this power app’s features in Nancy’s article.
Want to recommend another app? Hit us up in the comments!