So when do you guys thing it will actually come out?

Late April, Early May...I believe they announced this already. >_>

Here from wikipedia: 
 

 Mac OS X release

On March 8, 2010, Valve announced that Steam was in development for Mac OS X and would be released in April 2010. Prior to this announcement, it teased the release through several images emailed to Mac community and gaming web sites featuring Valve game characters with Apple logos or featured in parodies of old Macintoshadvertisements.

With its release, Valve will include native Mac OS X, OpenGL versions of Left 4 Dead, Left 4 Dead 2, Team Fortress 2, Counter-Strike: Source, Portal, and the entire Half-Life series. Portal 2, due by the end of 2010, will be simultaneously released on both the Windows and Mac versions of Steam. Through "Steam Play", the Mac client will allow players who have already purchased compatible products in the Windows version to re-download the Mac versions at no cost, allowing them to continue to play the game on the other platform. The Steam Cloud will be cross-platform compatible. Multiplayer games are also cross-compatible, allowing Windows and Mac players to play with each other.

well since they said april last month, im crossing my fingers for late april X)

There is a closed beta here.

lol the way valve works on things, they are just going to keep on delaying it :P 
 
it said late April and what people said above me late April.