Sometime late last year I got an email from Verizon about Playlinc. I thought it looked lame at first like a gamespy arcade rip off or something similar to it. However, I realized I was wrong when I gave it a try. Playlinc was easy to set up and I logged on to it using my normal aim screen name. What I like most and a pretty unique feature is Playlinc can host a server for a bunch of different games. For example, I can host my own COD2 server at one of Playlinc's data centers for free. I can change the name of the server, select the server location, maps, game type, etc. Also, Playlinc has built in VOIP. It has a bunch of other features too and some similar to xfire. It's all free so give it a try sometime.
http://www.playlinc.com