We've done a nice successful irc game recently, so I think it's fair to say it works.
For people interesting in joining one, or starting one, this thread can be used for putting up times, games, questions, discussion of current ones, and so on.
If you're not sure what any of this means, do ask. It's fun and can be as casual, simple and easy to do or as hardcore, expert and intense as you'd like it to be.