allround Emu sites
www.pocketgamer.org
www.zophar.net -> theres a link on the left for pocket pc emus
havent a clue about external keyboards as I dont have one
morphgear is supposed to be a god allround emu - megadrive sorry genesis/snes/nes/sms/gg/gbc
MameCE is a good arcade emu I >think< it might support neogeo, not sure
personally I use pocket nester (
www.jetech.org)for nes stuff
pocket snes bleeding edge for snes
there is a free megadrive/genesis emu pocket genesis , but its very slow still
castce is a good atari st emu
pocket64 is an excellent c64 emu (costs about 3-4 euros/dollars from
www.clickgamer.com)
pocket atari is a buggy but good 8bit atari emu
pocketvcs (clickgamer as well) is a good atari 2600emu
...gba emu??...getting into warez territory with that seeing as it and its games are still commerically available...just buy one and keep mario happy :)