[br]An official announcement from Valve now states that Steam and the Source engine will become available on OSX. Valve's library of games including Left 4 Dead 2, Team Fortress 2, Counter-Strike, Portal, and the Half-Life series will be available in April this year. Gabe says: Valve are also announcing a new Steam technology - Steam Play. Jason Holtman tells us more! These versions will not be emulations but full native conversions according to John Cook The recently announced Portal 2 will be Valve's first simultaneous release for Mac and Windows.