ZodTTD has updated his Gameboy and Gameboy Color emulator Gameboy4iPhone.

Changes:

– Exclusively supports the new 2.x.x series firmwares.
– Fixed the controller input to allow for 5+ touch points.
– Fixed up the audio playback. Sounds great!
– Improved performance by removing magnification filters in landscape and portrait views. I kept the aspect ratio so things look good still.
– Lowering and raising the volume now works properly when using the L/R buttons.
– Should be a lot more stable!

http://www.zodttd.com/forums/showthread.php?t=3175