Now you can enjoy Day of Defeat: Source, the WWII mulitplayer classic from Valve, on your Mac! Assume the role of infantry, sniper or machine-gunner classes and experience the intense online action set in Europe during WWII.

Team Fortress 2 (TF2), the game PC Gamer magazine's editors have called the most fun game ever made, is now available for the Mac via Steam, a leading online platform for games with over 25 million accounts worldwide.

Like all the titles Valve has brought to the Mac platform, TF2 features Steam Play allowing gamers to make one purchase to play the game on both the PC and Mac. In addition, TF2 supports cross platform play -- so Mac gamers can play against/with PC gamers.

Those who purchase TF2 for the Mac will receive a free set of "earbuds" for their favorite player character. Purchase the game this weekend can save 50% off the regular. Or, try the game now via the Team Fortress 2 Free Weekend happening now on Steam.

In addition to all the TF2-Mac goodness, a new single player training mode has been rolled out for both PC and Mac.

Don't have Steam? Get it here.

Valve and Prima today launched the first set of in-game Prima guides on Steam. All the guides are readable in game via Steam's UI overlay functionality, as well as being available outside of game. The launch collection of guides available now on Steam include Dragon Age: Origins, Just Cause 2, and Battlefield: Bad Company 2.

To celebrate the launch of Prima guides on Steam, all the launch titles are available at 50% off their regular price.