Xerox have released a patch for this, go to their web site and search for "Repair 10.6.8" download.
Or alternatively go to the Electro Music site below, where I first found the fix. Follow the link below, scroll down through the thread to find the patch/fix installer this guy created it works.
In fact if you follow the thread, he sent the fix to Xerox!
I found that the fix works best if you remove the printers, then Ctrl Click in the 'Printers' panel and select 'Reset printing system....'.
Then re install the Xerox printers, and then run the Repair patch. I have also been able to push the fix out using ARD.
Cheers
Phil
electro-music.com :: View topic - OS X 10.6.8 update kills network printing + a solution
''The OS X 10.6.8 update will kill network printing to most Bonjour laser printers. I suggest you all wait until Apple sorts this out.
The problem is this:
If you print to a Bonjour network printer from say Xerox .. .. what happens is that the printer queue will automatically pause.
The attachment is a zipped dmg file containing a pkg installer file made with Apple´s package maker.
What it does is replacing the broken files ( see my previous posts ) .
It might be smart to repair permissions after the installation.
The package file kan be installed over a network using ARD ( Apple Remote Desktop ). As previously stated the fix is intended for and it has been proven to work with a wide range of network laser printers. In all cases tested a reinstallation of the original printer drivers weren´t needed. You will of course have to restart the printer queue.''