Stella

Stella is an open source multi-platform Atari 2600 emulator, and one of the only Atari 2600 emulators that is in active development. Stella was originally developed by Bradford W. Mott for Linux, before the emulator was ported to numerous other systems including Windows and Mac OS X.

While Bradford has now ceased his own personal involvement with the Atari 2600 emulator, another talented developer took the reigns as being the primary maintainer of the Stella project. That developer being Stephen Anthony.

There has been numerous people who have worked on Stella over the years which has helped it become regarded as the best Atari 2600 Emulator available. The current plans for Stella is to continually improve and increase its ability to be ported to other platforms, as well as replicating and fixing some of the more complicated bugs in the emulation of the TIA.

Please note, that if you appreciate these developers work. They are openly accepting donations to help spur development. You can find the information at there official website here.