PowerShell in Action
So I went and purchased the Windows PowerShell In Action book by Bruce Payette and so far I've enjoyed it. It eases you in nicely to powershell and then goes right into the depths of creating scriptbocks and advanced functions. I think it helps quite a bit to be a knowledgeable scripter before hand. This book seems to target admins that already know how to script-manage their environment and instead teaches them how to use that knowledge in powershell instead.
I, on the other hand, still have lots to learn using PowerShell. 