Check out Retrogames and VG-Network for all the latest Console Emulation news.

Hand-Held

Nintendo Game'n'Watches - who could of made it through the eighties without playing one of these. Games are emulated as separate programs. They include Donkey Kong Jr, Manhole and Mario Bros.

Megadrive/Genesis

Genesis Emulation info
Sega - Probably won't find much about Megadrives here!

SNES

SNES9x - Homepage of the best Windows SNES emulator.
Nintendo

Nintendo 64

Official UltraHLE Site - Official Homepage for the Best N64 emulator.
Nemu64 - Homepage for another improving N64 Emulator.

Other

PC Engine (TurboGrafx)
NeoGeo for Life