MAME PC Emulator
MAME Mac Emulator
LOTS of emulators :)
Norbert Kehrer's Java Space Duel emulator!
For emulators, sorry, but I cannot help with ROM images, so please don't email me asking for them. But they are out there if you know how to use Google.
Or, try a classic old home game system where some of my games were ported:
The 2600 is back...sort of!