First there were the bits of OS X information found in the latest Steam UI beta. Then Valve began sending mysterious images of their game properties to various blogs pointing to their games being available on the Mac. Finally, after teasing the Mac gaming community for weeks, Valve has announced that their social gaming service, Steam is in fact coming to the Mac.

Steam for Mac will be available as a public beta beginning sometime in April. The announcement comes with word that all of Valve's current lineup will be available on the Mac on day one, including the newly announced Portal 2.

If you're a Mac user who just happens to have a Windows machine with Steam already installed, no worries. You can use the same license for all of your Valve games on your Mac. Just sign in with your account and download your Valve games. Valve is offering this ability to third-party game developers. So keep a look out to see if your favorite game's developer begins offering the service.

For Mac users unaware of the awesomeness of Steam, we have a quick beginner' guide to all the features Steam brings to gaming. We also had a chance to ask Steam's Project Manager, John Cook about porting the service to the Mac. 

Here's all the important info from the Steam team:

Valve announced today it will bring Steam, Valve's gaming service, and Source, Valve's gaming engine, to the Mac.

Steam and 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.
 
"As we transition from entertainment as a product to entertainment as a service, customers and developers need open, high-quality Internet clients," said Gabe Newell, President of Valve. "The Mac is a great platform for entertainment services."
 
"Our Steam partners, who are delivering over a thousand games to 25 million Steam clients, are very excited about adding support for the Mac," said Jason Holtman, Director of Business Development at Valve. "Steamworks for the Mac supports all of the Steamworks APIs, and we have added a new feature, called Steam Play, which allows customers who purchase the product for the Mac or Windows to play on the other platform free of charge. For example, Steam Play, in combination with the Steam Cloud, allows a gamer playing on their work PC to go home and pick up playing the same game at the same point on their home Mac. We expect most developers and publishers to take advantage of Steam Play."
 
 "We looked at a variety of methods to get our games onto the Mac and in the end decided to go with native versions rather than emulation," said John Cook, Director of Steam Development. "The inclusion of WebKit into Steam, and of OpenGL into Source gives us a lot of flexibility in how we move these technologies forward. We are treating the Mac as a tier-1 platform so all of our future games will release simultaneously on Windows, Mac, and the Xbox 360. Updates for the Mac will be available simultaneously with the Windows updates. Furthermore, Mac and Windows players will be part of the same multiplayer universe, sharing servers, lobbies, and so forth. We fully support a heterogeneous mix of servers and clients. The first Mac Steam client will be the new generation currently in beta testing on Windows."
 
Portal 2 will be Valve's first simultaneous release for Mac and Windows. "Checking in code produces a PC build and Mac build at the same time, automatically, so the two platforms are perfectly in lock-step," said Josh Weier, Portal 2 Project Lead. "We're always playing a native version on the Mac right alongside the PC. This makes it very easy for us and for anyone using Source to do game development for the Mac."

Support for the Mac in Source and Steamworks is available to third parties immediately.

Expect to see a Mac|Life team on Steam as soon as the beta goes live.