Use two computers with one printer

Printer Sharing (This is good for Windows 2000, XP and Vista)
Sharing will be very easy if your network is working.
You need to consider the computer where the printer connected as the "Host" and the other computer that wants to print to that printer as the "Client".
Before you do such sharing, you need to acquire each computer's IP address.
You can do it by accessing MSDOS Prompt and typing in ipconfig/all. Write down your IP addresses and the share name on a paper.
For your Host:
Install the driver, make sure that you can print on direct bi-directional connection (such as USB).
Go to Control Panel >Printers and Faxes* >Sharing >Share this printer >Type in your share name, good example is PRINTER (this is case sensitive).
For your Client:
Install the driver, make sure that you can print, same with the Host.
Go to Control Panel >Printers and Faxes* >Properties >Ports >Add Port >Add local port type in \\ (the IP Addressof the Host) \ (share name), click OK.
ex. \\192.168.1.3\PRINTER (watch your backslash, no spaces)
*Term used is "Printers" for Windows Vista and Windows 2000

If the printer doesnt have a network port or wireless capabilty, then you can use windows file and printer sharing option. From printer window in control panel, right click the desired printer and then click sharing. Then add the printer in the 2nd computer by going to the network places and browsing to the host computer where the printer is installed.
Note: File and Printer sharing should be enabled in both computers