The speculation is true. Blizzard has announced Diablo III, and they have a website up with some info, movies, screenshots, artwork, and other goodies.
For those who are into hack-and-slash action rpgs, your life is pretty much over when this game comes out.
http://www.blizzard.com/diablo3/
Be sure to check out the gameplay movie (and you can download high-res versions of all movies). It really shows off the art and new Diablo engine like the physics and the combat mechanics. And I am really liking the Barbarian class so far. Omega SMASH!