Joel,

http://www.delorie.com/

g++/gcc online documentation, and book recommendations. Also, as far as how
gcc/g++ compare, they are pretty much an industry standard. Many *nix
programmers will use them over proprietary compilers. I'm trying to learn to
use them, as well as VC++ to keep my experience well-rounded. I'd recommend
you think of your personal goals and learn GNU while you're thinking of them
:)

HTH

Lucas Vogel