If you like the space-sim kind of games you should check out Vendetta.Its like EV Nova, but 3-D, and an MMORPG. True you do pay a subscription every month ($10), but its pretty fun, and the d/l of the game gives you an 8 hr free trial.
I know there is a playstation emulator out there for mac (PCSX)...its pretty good btw. As for a PS2 emulator, I don't think they have made one for PC or mac yet. Check out the site Zophar's domain. they have pretty good emu news.