Today, Valve has released the beta client for Steam for Linux. Valve leads the charge with Team Fortress 2, while third-party support comes in the form of nearly two dozen additional Steam titles (link doesn't seem to work if you're on a Windows based machine).
The beta for the Steam for Linux client also supports the Big Picture mode, also currently in beta.
"This is a huge milestone in the development of PC gaming," according to Gabe Newell, Valve President and co-founder. "Steam users have been asking us to support gaming on Linux. We're happy to bring rich forms of entertainment and our community of users to this open, customer-friendly platform."
If you're running Ubuntu 12.04 and want to give the beta a try, you should send in your request for participation, if you haven't yet done so.
"An overwhelming majority of beta applicants have reported they're running the Ubuntu distro of Linux," according to Frank Crockett, a member of the Steam for Linux team, "We intend to support additional popular distros in the future; we'll prioritize development for these based on user feedback."
As with most betas from Valve, they will be adding more and more people over the course of the beta. More information can be found at the Steam Linux Community page.
It should also be noted that this release also comes with a new Linux driver from Nvidia! This driver, R310, is the result of a joint effort between Nvidia, Valve, and other game developers. Check out the news release from Nvidia.