How to set gcc 4.8 as default gcc compiler

How to set gcc 4.8 as default gcc compiler

I recently installed gcc 4.8 using brew on OSX 10.7.5. I can now compile
using gcc 4.8 by using g++-4.8 some_file.c or using the default gcc 4.2 by
using g++ some_file.c I want to use gcc 4.8 as the default compiler for
Xcode and if I type gcc at the terminal. I suppose I must alter
gcc-related links within dirname $(which gcc).
When I do ls -al $(dirname $(which gcc)) | grep 'gcc\|g++\|c++' I get the
following: lrwxr-xr-x 1 root wheel 7 Jul 31 12:17 c++ -> clang++
-rwxr-xr-x 1 root wheel 909360 Nov 18 2011 c++filt lrwxr-xr-x 1 root wheel
5 Jul 31 12:17 clang++ -> clang lrwxr-xr-x 1 root wheel 12 Jul 31 12:17
g++ -> llvm-g++-4.2 lrwxr-xr-x 1 root wheel 12 Jul 31 12:17 gcc ->
llvm-gcc-4.2 lrwxr-xr-x 1 root wheel 28 Jul 31 12:17 gcov-4.2 ->
../llvm-gcc-4.2/bin/gcov-4.2 lrwxr-xr-x 1 root wheel 52 Jul 31 12:17
i686-apple-darwin11-llvm-g++-4.2 ->
../llvm-gcc-4.2/bin/i686-apple-darwin11-llvm-g++-4.2 lrwxr-xr-x 1 root
wheel 52 Jul 31 12:17 i686-apple-darwin11-llvm-gcc-4.2 ->
../llvm-gcc-4.2/bin/i686-apple-darwin11-llvm-gcc-4.2 lrwxr-xr-x 1 root
wheel 32 Jul 31 12:17 llvm-cpp-4.2 -> ../llvm-gcc-4.2/bin/llvm-cpp-4.2
lrwxr-xr-x 1 root wheel 32 Jul 31 12:17 llvm-g++ ->
../llvm-gcc-4.2/bin/llvm-g++-4.2 lrwxr-xr-x 1 root wheel 32 Jul 31 12:17
llvm-g++-4.2 -> ../llvm-gcc-4.2/bin/llvm-g++-4.2 lrwxr-xr-x 1 root wheel
32 Jul 31 12:17 llvm-gcc -> ../llvm-gcc-4.2/bin/llvm-gcc-4.2 lrwxr-xr-x 1
root wheel 32 Jul 31 12:17 llvm-gcc-4.2 ->
../llvm-gcc-4.2/bin/llvm-gcc-4.2
which gcc-4.8 results in /usr/local/bin/gcc-4.8.
Steps to get this done would be very helpful. Please and thank you.