gpSP is a well known Gameboy Advance emulator available for a bunch of systems. It was initially written by Exophase.
Changes:
Support for Symbian^3
Better Audio
alpha channel for keys is now configured at video section (not in controls panel)
8-directional / 4 directional DPAD
Hidden A+B button areas
save/load states is now working
AEP-Emu (DE/EN)
DMG Page (DE)
EmuBit.pl (PL)
HomebrewWelt (DE)
Indie Retro News (EN)
NintendoMax (FR)
PlayerAdvance (FR)
Retroguru (EN)