Shacknews has a rather exhaustive preview of Valve's Team Fortress 2, coming to PC, Xbox 360 and PlayStation 3 as part of the Half-Life 2: Orange Box collection (also available via Steam, natch).
One interesting note at the end of the article states that the Valve offices, who are working on the Xbox 360 and PC versions (PS3 version is being done by EA UK), "regularly play cross-platform multiplayer games." However, the studio's Doug Lombardi said that the final game will not have cross-platform because it "introduces more problems than it is worth." He continued to say that if Valve were to implement cross-platform that it would be part of the initial game design.
Orange Box, which includes Half-Life 2, Episode One, Two, Portal and Team Fortress 2, is due out October 9.