Steam for Linux has been making steady progress since the official unveil earlier this year, with Left 4 Dead 2 even running faster in Linux than Windows. Yesterday, a new update appeared on the Valve Linux blog saying an internal beta starts next week and a private external beta for 1,000 users in October. No specifics were mentioned as to when the external one would start, but it will support Ubuntu 12.04 and higher. Only one game will be included (L4D2), as Valve wants the 1,000 users to see how everything is coming together. A sign up page will be launching before long, which Valve will provide more information for closer to launch. New Linux users are encouraged to wait for future releases when "more features are implemented along with improvements to the user install experience."