I've been having this problem as well (same circumstances as everybody else above, PEAP shows connected but I receive no IP).
I reported this to Apple just over a month ago, now, and like the rest of you, I've still heard nothing back, and I have to admit I'm getting pretty frustrated with the whole ordeal. It's understandable that a major new release will have glitches, and that I'll pay an early adopter cost in various inconveniences. But when I first called, they repeatedly and strenuously tried to tell me it's not their problem, that they don't support PEAP because "we can't possibly support every single feature in the operating system" (which I could accept if they were referring to some artifact of the unix underpinnings, but when it's someething that they went out of their way to give me a native OS X interface for, they are implicitly supporting it.
I can accept that their are bugs. I can accept that their support can't help me
yet. But I can't help but feel robbed when they give cop out answers and tell me it's my own fault for wanting to use this type of network, rather than simply acknowledge "we're working on it" (or maybe "we will work on that").
Bah.
[end rant.]