We've got two bits of news coming in for the guys who purchase their titles via Valve Corporation's Steam content delivery service. The site is has just announced that Ubisoft's Assassin's Creed title (also on the PS3, Xbox 360, and DS) is now available for download.

The game's PC port will carry four exclusive mission types, including the Rooftop Race Challenge, and the Archer Stealth Assassination Challenge. Also being made available on Steam is a pre-order for the upcoming Tom Clancy's Rainbow Six Vegas 2 (Xbox 360, PS3, PC) FPS.

The game itself is expected to launch on April 16 (Wednesday) next week, and will be available for download for a price of US$ 49.95. We note that the RSV2 pre-order is currently limited to the territories of North America and Canada.

Along with the pre-order, Steam is currently offering the original Rainbow Six title for the PC for a marked down price of US$ 19.95. Those interested in reading further regarding these deals will want to visit Steam for further details.