MESS is also a byproduct of MAME (They call it a sister emulator, but really it's a byproduct as alot of the code is reused). MESS is the Multi-Emulator Super System.

It emulates several consoles and older computer systems. Currently (at the time of me writing this node), it emulates (in some form or another); Adventurevision, Amiga 500 (NTSC), Amstrad PC1512, Amstrad PC1640 / PC6400 (US), Amstrad/Schneider CPC464, Amstrad/Schneider CPC6128, Amstrad/Schneider CPC664, Apple //c (3 variants), Apple //e (3 variants), Apple I, Aquarius, Atari 2600, Atari 400 (NTSC), Atari 400 (PAL), Atari 5200, Atari 7800, Atari 800 (NTSC), Atari 800 (PAL), Atari 800XL, Atom, Bally Pro Arcade/Astrocade, BBC MicroModel A, BBC Micro Model B, C64GS (PAL), C65 / C64DX (6 variants), CBM4064/PET64/Educator64 (NTSC), Colecovision, Color Computer, Color Computer 3, Colour Genie EG2000, Commodore +4 (2 variants), Commodore 128 (4 variants), Commodore 16/116/232/264 (2 variants), Commodore 30xx (2 variants), Commodore 364 (Prototype), Commodore 40xx (3 variants), Commodore 64 (3 variants), Commodore 80xx (4 variants), Commodore B128-40/Pet-II/P500 60Hz, Commodore B128-80HP/710, Commodore B128-80LP/610 60Hz, Commodore B256-80HP/720, Commodore B256-80LP/620 Hungarian 50Hz, Commodore Max (Ultimax/VC10), Commodore SP9000/MMF9000 (50Hz), CPS Changer (For Street Fighter ZERO, its more arcadeish - but oh well), Dragon 32, Enterprise 128 (2 variants), Game Gear, GameBoy, Inves Spectrum 48K+, Jupiter Ace, Kaypro 2x, KC 85/4, KC Compact, KIM-1, Laser 110, Laser 200, Laser 210, Laser 310, Laser 350, Laser 500, Laser 700, Lisa 2, Macintosh 512ke, Macintosh Plus, Master System, MC-10, Megadrive / Genesis, Microbee 32K, Microbee 56K (CP/M), Microtan 65, MSX1, MSX1 (Japan), MSX1 (Korean), MSX1 (UK), MTX 512, MZ-700, MZ-700 (Japan), Nascom 1, Nascom 2, Nintendo Entertainment System/Famicom (3 variants), Oric 1, Oric Atmos, PC (Not in the way I origionally though), PC Engine/TurboGrafx 16, PC8300, PC-AT (CGA, MF2 Keyboard), PCW10, PCW16, PCW8256, PCW8512, PCW9256, PCW9512 (+), PC-XT (CGA), PC-XT (MDA), PC-XT (VGA, MF2 Keyboard), PDP-1 (Spacewar!), PET2001/CBM20xx Series (Basic 1), Philips, P2000M, Philips P2000T, Pocket Computer 1350, Pocket Computer 1401, Pocket Computer 1402, Power 3000, Prologica CP400, Salora Fellow, Sam CoupÈ, Sanyo / Dick Smith VZ200, Sanyo / Dick Smith VZ300, Spectrum I+, Superboard II, System-80, Tandy 1000HX, TC2048, Texet TX8000, TI99/4 Home Computer (2 variants), TI99/4A Home Computer (2 variants), TK90x Color Computer, TK95 Color Computer, TRS-80 Model I (3 variants), TS1000, TS2068, UK101, VC20 (PAL), Vectrex, VIC20 (NTSC), VIC20 (NTSC), IEEE488 Interface (SYS4506), ZX Spectrum (13 variants), ZX Spectrum 128 (2 variants), ZX Aszmic, ZX-80, and the ZX-81.

It has also been ported to a number of platforms, including; Amiga, Digital Cameras, DOS, MacOS, RISC OS, Several Unixes and Linuxes, and finally several windows platforms.

Ummm... what else can I say about MESS? Well, it uses drivers much like MAME, and its understaffed and underfunded so all the help you could give them would be benifical (I can think of several consoles and systems that are not supported by MESS or have the best emulation they can get).