windows XP

Windows XP is now in the market. If I have 3 or more computers at home , can I install windows XP on all my three computers with only one user license and one copy, just like windows 98, or I can only install only on one computer only one time, or can I install only on one computer repeatedly if I for some reason replace the hard drive. Can someone tells what one user license means, its limitations differ from previous windows 9X or NT. What shall I do if I want to install on my 3 computers, do I need to buy 3 copies of windows XP (home edition).