Below you will find a list of online gaming services that I have found. I have used almost every singlr one of these services and they are all pretty damn good as far as getting players in one place and then getting them on thier way to playing against one another. Each service has certain games that they promote and you may have to look through a few of them to find one that sponsers the game you want to play. Almost all of them are both free and pay to play.
Most services offer both a free account and a pay account that gets extra benifits.
You will have to deciede if you want to fork over the extra cash for these extra benefits. This is the service that I use the most. They have a large selection of games and are always adding new ones. You can find all the hottest titles here and play them for free. Mplayer is a very uncontrolled yet pleasent enviroment to play.