I mentioned the Three20 open source library many months ago as a quick way to perform many utility operations within your app quickly such as photo-viewing, creating stylized buttons, and http caching.
Since then I’ve come across several tutorials that have really helped get more out of this library, and add some pretty cool functionality to iPhone apps.
First of all, the best place to find out how to use and do more with Three20 is the Three20 Google Group. These guys continuously share tips, and will answer all your questions about the library.
A couple of super useful tutorials that I’ve found are from Matt Vague:
If you’re just getting started Ray Wenderlich, the creator of the Space Game Starter Kit and co-author of the Learning Cocos2D book, has created a very straightforward beginners tutorial: Introduction To Three20
This is a very cool utility library that you will want to check out if you haven’t.