devkitPro

I am using codeblocks to compile my gba games. I set up codeblocks so that it would make an elf file. How can I compile the elf file to a gba game file?

I think this may be one of those situations where if you need to ask the question then you should not be trying to do this (ie leave it people like wintermute who have already provided you with these tools). The answer you are looking for is in the sample gba makefiles and referenced build files.