u can play with people on PC servers... but since we're still waiting for the 1.4 patch for mac and most of the PC users have upgraded.... u have a severely limited amount of servers.
go to the BF 2142 mac forums at
http://forums.ea.com/mboards/forum.jspa?forumID=4166
It's a good game, but as most people in that forum would agree, most of us would be happier if we had bought the PC version and were running it in bootcamp because of a) performance, b) stability, c) lack of patch 1.4 for mac (taking FOREVER), and d) expansion pack is NOT available for mac, and there are no plans to make it available either.
I mean... how can u port a game and NOT port the exp pack.... without even PLAN to port it?
you might want to get COD4 and run it in bootcamp (u can download the demo and try it) or get Quake Wars, which aspyr is porting (although i don't know why it isn't out yet... and why they haven't given us an estimate)
I played the PC demo in bootcamp while I was waiting for the mac version to come out, and the PC demo definitely had better performance (on the same system, of course)