Valve's Robin Walker had an interview with Develop Online today where he announced that Team Fortress 2 is now and will always be FREE. Being one of the biggest PC games in the past 10 years this is a big deal. It will be interesting to see how going free to play will affect future game play, but one thing is for sure. With free games popping up left and right, Steam is going to put up one hell of a fight to competition like EA's Origin.
Update, here is the video from valve