|It should be. |
I've never used Vista but the following will work on XP and should on Windows 7 and Vista too.
The printer has to be "shared" on the the PC it's physically connected to before you can connect to it from another PC.
In order for PC 2 to map to the printer connected to PC 1, you need to know PC 1's IP address.
Once you have that info, you start the add printer wizard on PC 2and choose to add a 'Local Printer' (uncheck the box beside "automatically detect and install...." and hit 'Next'. On the window choose "Create a new port" and opt for the "Standard TCP/IP port" and hit 'Next'. Enter the IP address of PC 1 and continue through the wizard adding the correct drivers (have the CD in hand before you start) and it should work.
Since both computers are already in the same domain, you shouldn't be messing with whether the PC's are in a domain or a workgroup and I don't understand how you got there as it's not part of connecting to a printer.
Just for future reference, a netowrk capable printer is a lot easier to work with. You can buy "print server" devices that provide network connectivity if your printer doesn't have a network interface built into it.
It matters not how straight the gate,
How charged with punishments the scroll,
I am the master of my fate;
I am the captain of my soul.