via http://www.aep-emu.de/

Marat Fayzullin has ported his (commercial) GameBoy Advance emulator VGBA to the Android platform: VGBA for Android

Quote:
New in 3.6.12:
  • Enabled sampled sound channels.
  • Added configurable custom key mappings.
  • Added optional haptic feedback.
  • Restored MENU button on Android Honeycomb.
  • Finger joystick now shows up on tablets in portrait orientation.
  • Optimized joystick drawing routines.