Hi, I had the same problem with my HP Officejet 4215 after upgrading to 10.5 (and then 10.5.1 update). Emailed HP and they said they will NOT be writing any new drivers for the 4215, period. Not a happy camper, but I've solved this before so time to do it again...
The solution to using your HP 4215 (and MANY others) with an Airport (print only, of course) is found here:
http://www.linux-foundation.org/en/OpenPrinting/MacOSX/hpijs
You need to install 3 items to make the printer print through the Airport:
1. hpijs-2.7.10-UB
2. Foomatic-RIP
3. ESP Ghostscript
Everything is found or referenced at the above Open Printing link. In fact the hpijs driver will not install at all unless it finds both #2 and #3 so do them first (or try it and find out for yourself ). 🙂
It's all explained at the link but here is how I did it:
Installed the 3 items above then go into System Prefs, then Print & Fax, then find and double-click on your printer, select Info, then select Driver, then find the Foomatic/hpijs driver that is recommended for your printer. Voila! Airport printing works again, under 10.5.1 even! Or you could wait for HP to write a new driver...
Hope this helps. Good luck!