Game Boy Advance
Gameboy Advance Development
Jeff Frohwein's Software/Hardware Dev'rs
Reiner Ziegler GBA Development
Darkfader.net - Gameboy Advance
CowBite Virtual Hardware Specifications
Inofficial documentation for the CowBite GBA emulator by Tom Happ
Gameboy Advance Technical Info
Programming The Nintendo Game Boy Advance
This book was not released in book stores due to legal problems with Nintendo. As a result, the e-book edition is available for free as a downloadable PDF e-book.
A GCC based SDK for the Gameboy Advance, running on Mac OS X.
A programming/hobby development site. Contains good tutorials.
GBAGuy's Lair GBA ASM Tutorials. What is IE6?
The Socrates Gameboy Advance Development Engine.
The Pern Project
Programming tutorials, demos, and source code for the Nintendo Gameboy Advanced.
Toolchains of choice for homebrew game development.