Phoronix posted the latest updates on Valve's Linux plans

For those that have doubted the exclusive Phoronix claims for quite a while now that the Steam client and Source Engine are in fact being ported to Linux, the doubts can be nearly laid to rest. Even I began to wonder how long it would take before the clients for their popular games would be publicly released under Linux. However, after confirming the information perhaps a bit too soon, their level of Linux interest is much more clear after spending a day at their offices. A meeting topped off the day with Gabe Newell regarding Linux where he sounded more like a Linux saint than an ex-Microsoft employee. Valve does have some great plans for Linux beyond just shipping the client versions of Steam and their popular games on the Source Engine.

  Valve's Gabe Newell Talks Linux Steam Client, Source Engine