Use Tclock in XP to get a cool tiny start button on the taskbar. Go to properties -> taskbar and select \"customize start button\". You can\'t customize the text or load an icon BUT you can make the caption a . to reduce the button to a small green square, and select \"flat start button\" to make it transparent (invisible!).
http://homepage1.nifty.com/kazubon/tclock/The clock is great too.