Here is the latest project from FluBBa. Goomba is a Gameboy Classic emulator for the Gameboy Advance. In case you do not have a GB-Bridge and own a flashcard this might save you a little money. Here are the release notes for this version:

Initial release. GB-Z80 done, probably some bug left. Memory done, only 8kbytes of external ram. LCD done, windows not fully working. Sound done, waveram not allways updated correctly. MBC’s, most done, no clock or ram paging yet. Controller done. Serial done, should act like real. Savestates done, not found any problems. Link Transfer done, as usual works when it wants to.

http://goomba.bornonapirateship.com/