The following procedure got the Phaser 6010N that I bought last week working fully with Ubuntu 12.04 64-bits with no complexity.
TL/DR: download the 32-bit drivers package from Xerox, get the .deb package from downloaded archive. Open terminal, cd to directory containing the .deb package. Execute the following three commands to install 32-bit libs, 32-bit CUPS, and the 32-bit drivers from Xerox, after which installing the printer normally via the system menu should find those drivers without further effort.
sudo apt-get install -y ia32-libs
sudo apt-get install -y libcupsimage2:i386
sudo dpkg -i --force-architecture xerox-phaser-6000-6010_1.0-1_i386.deb
A Detailed Procedure to do the above follows:
1. Download the (32-bit) Linux CUPS DEB print driver from Xerox here
http://www.support.xerox.com/support/phaser-6010/downloads/enus.html?operatingSystem=linux
which gives you a zip file called 6000_6010_deb_1.01_20110210.zip in your Downloads directory, which you
can double click on to have the archive manager find and extract the real contents, the driver package,
xerox-phaser-6000-6010_1.0-1_i386.deb
best extracted to your Downloads directory as assumed in the next step.
2. Open a terminal and execute the following four commands, assuming you've placed the driver
package in your Downloads directory, after which you may close the terminal.
cd ~/Downloads
sudo apt-get install -y ia32-libs
sudo apt-get install -y libcupsimage2:i386
sudo dpkg -i --force-architecture xerox-phaser-6000-6010_1.0-1_i386.deb
3. Install the printer as usual by going to Printing item in the System Settings window or the Printers item on the system menu (top right) and clicking the button '+Add'. I found the Phaser 6010N on the network as I'm connected by ethernet, by clicking on "Network Printer', waiting for it to be found and selecting it. Then I chose the option 'AppSocket/JetDirect network printer via DNS-SD', clicked the "Forward" button and was able to immediately print a color test page.
