In my office, we use IPP exclusively for networked printers. This includes an older HP LaserWriter MV4 and an Electronics for Imaging Fiery X3E. When I installed 10.4, it took me half a day to figure out how to print again! Configuring IPP was easy as usual, but for some reason, the new printer utility is not generating the correct Queue Name value. In fact, it appears to be generating it from the 'Name' you give the print spooler on your local machine, instead of requesting it from the printer itself.
To make a long story short, I tried using HP Jet Direct for the HP printer and voila, it just worked. I left the queue name blank, and simply put in the IP address and picked the correct PPD. Then I went ahead and tried the same thing with the Fiery Printer ... it also worked, though I'm not sure exactly why or what was different about HP Jet Direct as opposed to IPP.
So if you're having trouble getting your networked printer to work using IPP, try using HP Jet Direct instead ... your mileage may vary.
Mac OS X Hints
http://hints.macworld.com/article.php?story=20050506121833931