Install XCode 3.2.6 on Mac OS X 10.7 Lion

I was trying to compile GWT DevMode Plugin for Firefox on Mac OS, found the source code is configured to use mac os 10.5 sdk, which is included in xcode 3.2.6 but dropped by the later versions of xcode. The follow steps are what I did to install xcode 3.2.6 on Mac OS X 10.7 Lion:

1. Download XCode 3.2.6 from https://developer.apple.com/downloads. (You need to sign up and login.)
2. Mount xcode_3.2.6_and_ios_sdk_4.3.dmg
3. Open /Applications/Utilities/Terminal.app and run the following command:

   export COMMAND_LINE_INSTALL=1; open "/Volumes/Xcode and iOS SDK/Xcode and iOS SDK.mpkg"