Hatari is an Atari ST/STE/TT/Falcon emulator. Hatari supports the emulation of most of the ST and STE hardware, including some special tricks like raster interrupts, border effects and PSG sample sound. Unlike many other Atari ST emulators which try to give you a good environment for running GEM applications, Hatari tries to emulate the hardware of a ST as close as possible so that it is able to run most of the old ST games and demos.
WWW: http://hatari.tuxfamily.org/