I just found out there is a very useful tool built into XP and Windows 2003, called diskpart.exe. This program will allow you to expand a windows disk volume to larger disks. I had the chance to use this recently to increase a server from three 36 gig drives to three 72 gig drives. This program allowed me to extend the drive space with out having to backup and restore to new volumes. This program is great. It works on windows 2000 and windows 2003 and also XP.
Here is the microsoft.com link for how to use DiskPart – KB325590
You can download the program from here if you do not have windows 2003 – DiskPart
The next time you are upgrading take a look at this program.