Allow me to be tragically late to the party in pointing out that Bruce Payette’s PowerShell in Action is now available.
As shown by its Amazon page, the reviews are immensely positive.
Unfortunately for me, I’ve sequestered myself from reading any of the PowerShell books until my own is complete. This one, however, calls longingly from co-workers’ desks as I walk down the halls :) Conversations with Bruce are always interesting, and this book is sure to not disappoint.