If HPLIP is not installed, install it, including the hplip-gui package (I think that's a separate package in Ubuntu). It's in the Ubuntu repositories.
Then start the HPLIP GUI with root privileges: sudo hp-toolbox in a terminal. Use HPLIP to discover the printer. If an HP printer works with Linux, HPLIP will find it.
If the printer is connected to another computer, it must be configured as "shared" on that computer. If it's directly connected to the network, it should show up.
Last edited by frankbell; 11-21-2011 at 10:06 PM.