Sometimes after a clean reinstall of your system, you want to reinstall one of the previous versions of the iOS SDK, maybe your not fully happy with xcode 4 yet or have a project that will only compile with an older version without somechanges you do not wish to make.
The older versions are available with a little digging on the following URLs
- iPhone SDK 3.1 with XCode 3.2.1
- iPhone SDK 3.1.3 with XCode 3.2.1
- iPhone SDK 3.2 with Xcode 3.2.2
- iPhone SDK 4.0 with Xcode 3.2.3