This evening I was banging my head against a wall trying to figure out why I couldn't print to my HP LJ1200 printer over TCP/IP from my new Powerbook with OSX, version 10.5.2. I finally stumbled on to this thread from Apple Support, and found the missing ingredient: Add "LP" for the queue name.
Now, when one sets up a new printer under Leopard, you begin with system preference and printer& fax. After clicking on the "+" sign to add a new printer, I elected LPD for protocol box. Next, I enter in the IP address for my HP printer. After that, you come to the third item, queue name. For some reason, Apple has the statement "Leave blank for default queue." right under this box. When I left it blank, my print jobs kept stalling. I tried different drivers, differnt options, but nothing worked.
Finally, I deleted all my printers and started over. This time I entered "LP" as the queue and guess what? I'm printing. By the way, this solution worked with the generic postscript printer and the HP LJ 1200 drivers as well.