This is the preeminent resource center for software development on the Nintendo® Game Boy Advance™ video game console. It is a major arm of the Fanhacker’s Toolkit, which endeavours for homebrew and hacking fans of popular games.
The meat of this compendium can be found in the Awesome List, though beware it is still very much a work-in-progress. There is also a great reformatting of Martin’s GBATek, the NO$GBA documentation extract. Projects with the FHTK include: