I thought Xcode would come with these compilers. Can i download them manually? Where do i find them?
If you downloaded the standard xcode for OSX it should already be installed to /usr/bin/gcc. If not, you need to reinstall it and follow the instructions on the screen.
Alternatively you can install gcc from your OSX dvd.
Xcode 4.3+ the 'Command Line Tools for Xcode' are optional. They can be found here: https://developer.apple.com/downloads