XP uses some form of copy-protection that prevents me from using the same CD on more than one computer on my network, doesn't it?????!!!!!!
You can use the same CD you just need a different license. When you purchase a piece of software what you're really purchasing is the legal privelage to use the software, you don't actually own it. In order to install the OS on another PC you need another license, thus you need to buy another copy of XP if only for CD-Key.