Xcode 3.2.6 Release was released on 6 Mar 2011 and requires macOS 10.6.4+.
It can be downloaded from https://download.developer.apple.com/Developer_Tools/xcode_3.2.6_and_ios_sdk_4.3__final/xcode_3.2.6_and_ios_sdk_4.3.dmg.
Release notes are located at https://download.developer.apple.com/Developer_Tools/xcode_3.2.6_and_ios_sdk_4.3__final/xcode_3_and_ios_sdk_4.3_readme.pdf.
The SDKs it contains are:
- iOS 4.3
The compilers it contains are:
- clang 1.7 (Build 77)
- LLVM-GCC (Build 2335.6)
- GCC 4.0 (Build 5494)
- GCC 4.2 (Build 5666)