Dear goodness here we go again. Two monumental sequals are now in the works at Blizzard, and the newly announced Diablo III looks to be incredible. IGN has coverage including gameplay videos and some details about classes and abilities. Gamespot also covers the same event, the Blizzard Worldwide Invitational.
Diablo III will be available for PC and Mac, and it will be available whenever any Blizzard game is ready. "When it's ready," they say.
So, in 2010, be ready for Diablo III!