In
For those who have to ask, the answer is almost certainly that
it's not worth upgrading.
XP Professional and XP Home are exactly the same in all respects,
except that Professional has a few features (mostly related to
networking and security) missing from Home. For most (but not
all) home users, these features aren't needed, would never be
used, and buying Professional instead of Home is a waste of
money.
For details go to
http://www.winsupersite.com/showcase/windowsxp_home_pro.asp
http://www.microsoft.com/windowsxp/whichxp.asp
http://www.microsoft.com/windowsxp/home/howtobuy/choosing2.asp
Also note that Professional allows ten concurrent network
connections, and Home only five.