Acquiring roms that you do not own a hard copy of is illegal. Remember, to emulate NES games with Nestopia you need to have the NES roms. Sure, Nestopia works if you want to emulate NES games on your Mac at the barest level, but it could be so much more. Unfortunately, the Mac version does not have all of the fancy emu stuff the PC version comes with.
Nestopia is a really good emulator on the PC.
