Pat called today and needed to transfer his iTunes library from a Windows XP machine to his new Vista machine. We didn't have any great advice besides buying a Mac, but did find this step-by-step process that explains how to do it. [1]
Links:
[1] http://www.somelifeblog.com/2007/07/vista-transfer-itunes-library-and.html
[2] https://www.paypal.com/cgi-bin/webscr?cmd=_xclick&business=rick@yourpcpartner.com&item_name=Buy