I've added the old GBA Emulator, CowBite, to my website. To those unfamiliar, CowBite was a project I took up on a whim while in the midst of graduate school. The main purpose of it was to provide a debugging environment for GBA development (it actually had a rudimentary C code debugger built in). Unfortunately I was very overwhelmed at the time - first with my master's project (eventually released to public domain as Orn), and then with my first game industry job at Red Eye Studios. Thus CowBite got off to a good start but was never able to emulate that many games.

The story does have a happy ending though - while plumbing the depths of the GBA architecture I wrote a the CowBite Specification Doc, which was used by a lot of homebrew developers in the absence of official Nintendo documentation (which actually wasn't very good, oddly enough).

To any programmer with an interest in writing an emulator, I'd highly recommend it for the sheer fact that you come away from it feeling like you now understand computers (and programming) completely. Just thinking about it puts me in the mood for coding...