Yeah, he can. All you have to do is share your printer. Assuming you are using the same router and sharing the same connection.
I assume you're on windows XP - what you need first is your pc name, right click on my computer, go to properties > Computer name > should have your full computer name and workgroup.
note that down, then go to control panel > printers. Find your printer in there, right click it and then click "Sharing".
Click on "Share this printer", name whatever else you want, hit ok.
Go to your roomie's computer.
click on start, go to run
type in the name of your pc with two backslashes.
Ie: \\alleycat or \\pcname
if you guys are networked properly, you'll see your printer listed once that opens.
Go to control panel > printers on your roomie's PC.
drag your printer from that window, to your friend's printers list.
It may ask to install files, do so.
After it's done, then you're set. Whatever he prints, he should have the option of selecting your printer on the network.
This is pretty much the basic rundown, if you need further assistance do let us know.
