Rapid GUI Programming with Python and Qt: The Definitive Guide to PyQt Programming
Whether you're building GUI prototypes or full-fledged cross-platform GUI applications with native look-and-feel, PyQt 4 is your fastest, easiest, most powerful solution. Qt expert Mark Summerfield has written the definitive best-practice guide to PyQt 4 development.
The first few chapters brought me up to speed on Python itself. The chapters which dealt with PyQt were of course the most detailed and the most useful. I found myself getting frustrated with the "Dance of the Seven Veils": the book would touch on a topic briefly, explain how important it was, give an example, then hurry away to cover something else. By the time we got to the meaty, more thoroughly-explored examples, I was confused and slightly lost. Google filled in the gaps, so in the end it was all worth it.
All things considered, I think that Summerfield's book was worth the money. It rarely leaves my desk and never sits on my bookshelf. That's how useful it is to me.