A phone call to HP Support got me a CD a few days later with the G85 All-In-One drivers for OS X. I understand there is an update on the HP web site now, but I haven't tried it.
I was able to install from that CD and (no thanks to HP support) can now use the G85 printer from OS X 10.1.2. I have also scanned in OS X. This is on a PowerBook G4 Titanium 400. My G85 is connected via TCP/IP using a JetDirect 300X. The TiBook is on AirPort.
HP support claimed that 'TCP/IP isn't supported' when I couldn't get it to work at first. I eventually figured out that I have to launch 'AIO Communications' (an HP daemon) manually, for some reason the installer didn't set it up properly to launch automatically.
I have seen a number of posts claiming very slow printing or 'screwing up' of their systems. None of those posts specified if they are using the printer over USB or TCP/IP. On my Mac, connected via TCP/IP, it works as quickly as I would expect, and has not 'screwed up' my system. Good luck.
After some hours of frustration connecting my G85 with USB and Jaguar and using the new driver from HP I went to HP´s supportsite and I found this:
"Launch Print Center from the Utilities folder in the Applications folder.
2. Click Add Printer.
3. Select HP AiO Print or HP AiO Fax in the drop-down list.
4. Select your device in the browser list and click Add. Your device is added to the Print Center's printer list, with the suffix "(Print)" or "(Fax)".
5. Quit Print Center.
Do NOT select USB from the drop-down list to use the AIO device."
I had selected USB all the time, but after selecting AIO Print it worked fine. Hope this will help some of you.
HP drivers suck. I'm running them in X.2 and printing over an IP. It works but takes a few minutes a page, and thats just B&W. However gimp print drivers work fast when i need to print something that doesn't need to look professional. It has some issues but for fast B&W prints it rocks!!