I just got a new macbook pro and trying to setup my dev environment.
I downloaded xcode 4.2 from the app store and installed it, after this i installed homebrew and RVM.
Ima
I tried to download and install 4.1 for lion and this didn't even install (without a proper error message).
Now a colleague gave me this great link to GCC for Mac which worked like a charm:
https://github.com/kennethreitz/osx-gcc-installer
Don't forget to download the v2 if you run on > 10.7.0