Two weeks ago, Activision announced it would distribute several of its most popular PC games, including Call of Duty 2, via Valve Software's Steam download service . The move surprised many, since Valve had previously signed a deal with the publisher's archnemesis, Electronic Arts, which distributes retail copies of the Washington-based developer's popular shooter Half-Life 2.

Now, another EA rival has struck a deal with the megapublisher's partner. Today, Take-Two Interactive subsidiary 2K announced that it, too, would sell games via Steam. The first batch of games, which are due later this week, will include two top strategy titles from Firaxis Games: Civilization III and Civilization IV. Also included will be the high-seas adventure Sid Meier's Pirates! and the alternate-history real-time strategy game Shattered Union.

"We are excited to add Valve to our roster of partners in the digital distribution area," said Paul Crockett, an executive in 2K's strategic sales and licensing department. "Being included in their vast network will assist us in expanding the reach of our products to a much larger audience."

According to a statement released today by Valve, Steam currently has some 10 million customers for both its "core" products--which include advanced shooters such as Half-Life 2--and casual games, such as PopCap Games' Bejeweled and Zuma.

Oct 24, 2006