I wasn't able to play anymore once I upgraded my system (which I had to do in order to use pretty much >any other software< I'm on OS10.10.5 right now on a mac mini. Aya said she thought at least one active CD player is on Mac but maybe they keep an old one around in order to play. If anyone knows any tricks in this department, I'd be glad to know as I miss dropping in.
I play on a Mac Air. I had to buy the PC version from Gog.com (diamond edition) and installed it using Crossover for Mac. You just have to be mindful to ask the Gog.com folks for a unique cd key to go online / multiplayer mode. It was fairly painless to do this. I did the install in early September, so poke me over Skype if you have questions.
Crossover is a paid app, though... I'm reading good things about WINE (which Crossover is itself based on) but I'm a Windows guy and I'm not confident I could adequately explain how to use a program I can't actually use.
We had a few players back in the day who used Wine with no issues
I tried using Wine initially and it didn't load up properly for me, so I paid for Crossover. I don't remember if Wine wasn't loading NWN1 or NWN2 though, but it definitely failed for one of them.