If you have your Mac install discs handy, you can put on Xcode, which includes GCC, a weird but functional IDE, a slew of OS-X-specific tools and all the libraries you need.
This does include a perfectly ordinary command-line GCC, if you would rather avoid the Apple tools and use a plain old text editor.
If you want the newest release of Xcode, go to Apple
ADC, create a free account for yourself, and download it.