I happened to watch Sean McCown's Powershell for Beginners video over on Pragmatic Works this weekend. The video made a similar observation to Steve's comment in that Powershell provides a consistent way of interacting with things like Windows, SQL Server, Exchange, etc., and once you've learned the core concepts, branching out into other areas via snap-ins is pretty simple.

Learning Powershell is on my to-do list this year (I managed to get it configured to work with SS2005 this morning), so I for one would be interested in a review of this book down the road.