Mike Mearls discusses the PHB2 on Gamer Radio Zero
here. Some highlights: "If there's stuff in the Player's Handbook that you're like, 'hey, where's this class', it's probably going to be in the Player's Handbook 2." Also new classes -
a cleric that's a bit more on the spellcaster-y side,
a striker that's a "deadly and dangerous" kind of guy. The druid (I think the 3.5 druid, but I'm not sure) is the main example of a primal character, and other primal classes do things that will remind you of the druid, but in their own unique way. He lists the first letters of each class in the PHB2 - D, B, B, W, I, T, S, S (after this
correction). He also says "I think only three of those are classes that anyone has ever seen before. I think the other ones are all new classes, completely new to Dungeons & Dragons." However, when asked on his blog how many classes are new he says "Three are completely and utterly new. The rest are either classes or old concepts revisited." (
source)
The Shaman is mentioned as a class that fills the Leader role (
source). Rich Baker mentions it "includes some neat mechanisms for dealing with nature spirits". (
source)