Hey Greg, glad to hear that you are enjoying the book.
jQuery UI is relatively new -- in fact, it was just being formalized as jQuery in Action was going to print.
As my book is the most recent on jQuery, I'm afraid that there aren't any out there that cover the UI components.
You'll need to rely upon the online documentation until a second edition of jQuery in Action covering the changes gets published. (I know of no other jQuery books currently in the works -- but that doesn't mean someone isn't working on one on the QT).