It's hard to say if yesterday's rumor that a sequel to Borderlands is in development spurred Gearbox Software and 2K Games to officially announce the game this morning, but I don't really care. Borderlands 2 is a reality, and it's coming sometime between April 1, 2012 and March 31, 2013.
2K Games confirmed the news in a press release this morning, though you can also see that same text on the newly launched Borderlands 2 website. The site also points to a Game Informer link that confirms a 12-page feature on the game in its September issue. It's a cover story, and you can see the artwork for it above.
The sequel will feature "all new characters, skills, environments, enemies, weapons and equipment, which come together in an ambitiously crafted story," according to the press release. Pandora is also confirmed to once again be the game's setting.
New details will emerge in a few weeks when the game makes its public debut at Gamescom 2011. A US debut will follow one week later at PAX Prime.
Source: 2K Games