If you know the name of the printer (according to Windows, such as "PRN001" or maybe simply "My Printer Make"), then you can find out the address of it very much like other computers on the network.
To view the IP address of a machine connected to the network, click on Start, Programs and the Command Prompt, or you can click Start, Run, then type "cmd" and Enter.
This will bring up a black box with grey writing. Don't be alarmed by this. Simply type in "Ping [name]" and Enter, where [name] is the name of the machine (or printer), and if it includes spaces, must be placed in speech marks. So for example, "Ping PRN001" or "Ping "My Printer Make" ".
When you press enter, it will say "Pinging [name] (xx.xx.xx.xx)" where the xx's are the IP address.
Sounds long winded, but it's actually one of the quicker ways to find it...