Visual Boy Advance GX is a Game Boy Advance / Game Boy emulator based on VBA-M.

Features:

Wiimote, Nunchuk, Classic, and Gamecube controller support
SRAM and State saving
IPS/UPS/PPF patch support
Custom controller configurations
SD, USB, DVD, SMB, Zip, and 7z support
Compatiblity based on VBA-M r927
MEM2 ROM Storage for fast access
Auto frame skip for those core heavy games
Turbo speed, video zooming, widescreen, and unfiltered video options

Changes:

2.2.1 – August 14, 2010
* IOS 202 support removed
* USB 2.0 support via IOS 58 added – requires that IOS58 be pre-installed
* DVD support via AHBPROT – requires latest HBC

Plenty of legal GBA homebrew games to try out can be found here at PDRoms -> http://www.pdroms.de/files/gameboyadvance/

http://code.google.com/p/vba-wii/