FB Alpha is an arcade emulator supporting the following platforms;
FB Alpha also has WIP console drivers for Sega Megadrive/Genesis, ColecoVision, Sega SG-1000, Sega Master System/Game Gear and also PC-Engine/TurboGrafx 16/SuperGrafx.
The official releases target Microsoft Windows and can be downloaded from this site. The source code is also available to download and there are various other ports for other Operating Systems/Consoles.