I'm using one very succesfully via a Dayna Mini Etherprint. I've used this adapter for quite sometime with an NTR, 320 and now the 4/600, totally reliable. It's connected to my ethernet network and shared between a PowerMac, MacBook and iMac G5, all using (currently) 10.4.8.
Admittedly the printer is slow by modern standards, but for my occasional printing needs (I avoid printing things as far as possible due to the storage space required and to save trees!) it's ideal.
It seems you can even pick up brand new HP branded toner cartridges quite cheaply on ebay for these too (do a google search to see the compatible HP model).