1 To install gcc on mac just follow the link:

https://github.com/kennethreitz/osx-gcc-installer

2 to install homebrew:

http://mxcl.github.io/homebrew/

now try gcc with

gcc -v

you will see:

Using built-in specs.
Target: i686-apple-darwin10
Configured with: /var/tmp/gcc/gcc-5666.3~123/src/configure –disable-checking –enable-werror –prefix=/usr –mandir=/share/man –enable-languages=c,objc,c++,obj-c++ –program-transform-name=/^[cg][^.-]*$/s/$/-4.2/ –with-slibdir=/usr/lib –build=i686-apple-darwin10 –program-prefix=i686-apple-darwin10- –host=x86_64-apple-darwin10 –target=i686-apple-darwin10 –with-gxx-include-dir=/include/c++/4.2.1
Thread model: posix
gcc version 4.2.1 (Apple Inc. build 5666) (dot 3)

great! done.