Its official. Game publishing giant Electronic Arts today formally joined Valve's Steam service, as speculated earlier this week following the sudden appearance of the Spore end-user license agreement on the platform. Five titles are available now for purchase via Steam, including Mass Effect, Need for Speed Undercover, Spore, FIFA Manager 09 and Warhammer Online: Age of Reckoning, plus the Spore Creepy & Cute Parts Pack.

The games are apparently available without the controversial SecuROM DRM they initially shipped with. This is truly a testament to the popularity of Steam and a big win for Valve, considering EA traditionally has digitally distributed their internally-developed PC games only though its own EA Store and Steam competitors like Direct2Drive. Other recent EA releases expected to join the Steam lineup in the coming weeks include Dead Space, Command & Conquer: Red Alert 3 and Mirrors Edge.