This is a copy of the official svn repo that you can find on google code: http://code.google.com/p/box2d/
The difference is that I modified it so the Xcode project compiles properly. You can use that to learn how to compile a Box2D has a static library and how to use it in an iOS project.
Open the Xcode project:
$ open Contributions/Platforms/iPhone/iPhoneTestbed.xcodeproj
ALL_BUILD target and build.
To test in the simulator, choose the
iPhoneTestBed target and Run the
example, the dependencies will compile and the simulator will start.
The original source code is licensed under the zlib license http://en.wikipedia.org/wiki/Zlib_License