Activision and Treyarch announce that a double XP weekend is now underway for Call of Duty: Black Ops on all platforms. Here's word:

We wanted to let you know that Treyarch is hosting their first Double XP multiplayer weekend starting at 10:00am Pacific, Friday, February 4th through 8:00am Pacific, Monday, February 7th. Anyone playing in multiplayer matches on the Xbox 360, PS3, Wii or PC versions of Call of Duty: Black Ops will earn double XP rewards and level up.