Sorry for the pun, but Wildpalm have done it again. Not content with forcing a ZX Spectrum and a Nintendo Gameboy into Series 60, they've now launched Sonic Boy (http://www.wildpalm.co.uk/SonicBoy.html), a Sega Game Gear and Sega Master System emulator. Well worth checking out if you have some legal ROMS.

Of course you could pay for the Emu. Or you download SMSplus (its freeware) for S60 and you can play MS/GG Games on your Phone without having to pay for the emu !