My favorit is still the book of Johan.

If you are a good programmer and only need the book for a "brief" introduction (as while the normal work life you surley won't need more than the documentation and this forum here ), the first edition of C++ GUI Programming with Qt 4 is free for download. (Don't have the link right now, but you'll easily find it) It should be enough to guide you through the basic Qt techniques in a structured manner, so that after that you could easily start programmint with Qt and learn further while coding.