2600 Emulator for Mac OS XOverview
This emulator which was written in 100% assembly is based on of Paul Robson's A26 emulator. It runs most Atari 2600 games at an excellent speed even on slower PCs. It also supports games with the Parker Brother's chip and TigerVision's chip. There is now also support for paddles, the Stelladaptor, and Atari Trak-Ball controllers. Definitely one of the best Atari 2600 emulators out there. This is the Mac version.