Hattrick is the worlds greatest and most popular online football manager game.
And its completely free!
In Hattrick, you run your own football team and compete against other human players from all over the world. All you need is a web browser. Matches are played in real time a couple of times a week. You can log on at any time to check the status of your team, issue training orders, trade players - or just hang out with other Hattrick users.