It's actually pretty simple. Install SQL Server on the server computer. You will need to make sure that the server allows incoming requests. SQL Server uses TCP/IP ports to communicate from one computer to another. By default, the port is 1433. So, in its simplest form, allow incoming traffic on the port, and you're all done.
Start -> Control Panel -> Network Connections
Right click on your network connection
Click Properties
Click Advanced
Under firewall, click settings.
Click the exceptions tab, and add one for port 1433.
Usually, this is all that is required.
-George
"The great things about standards is that there are so many to choose from." - Fortune Cookie Wisdom