XP Customization

PatchXP patches Windows to let you use non-Microsoft themes

http://www.belchfire.net/article205.html

tgtsoft sells Style XP
http://www.tgtsoft.com/

An easy tutorial on modifying your boot and login screens is at http://www.extrememhz.com/winxpcust-p2.shtml

Some cool themes available from http://www.lightstar1.com/ complete with FAQs on how to install them.