I have found some useful iOS libraries.
- Three20 : Framework developed by Facebook for their iPhone App.
- MBProgressHUD : To display a progress activity window.
- DSActivityView: To display a progress activity window.
- CorePlot : To draw colorful graphics.
- TISwipeableTableView : Swappable Cell to display a menu, like the Twitter or Facebook Apps.
- MGTwitter : A custom Twitter engine.
- Cocoa / Cocoa Touch Controls: Offers a great selection of open source controllers and libraries.
- iOS Frameworks : Offers a great selection of open source controllers and libraries.
- ASIHTTPRequest : For everything related to web-stuff.
- EGOTableViewPullRefresh : Pull to refresh library.
- SFHFKeychainUtils : If you are working with passwords.
- GDataXML : Helped me a lot with parsing XML files. More on this