The Syamntec product that backs up Windows 2003 Server is called LiveState. I use it and it's great, it not only takes full images but incremental ones as well. I use it in conjunction with veritas to ensure all my systems are backed up.
Another great function of this software is that you can browse the backup image, so for instance if your SYSTEM file gets corrupt then you load the server from the Livestate CD, browse to the image file (LAN, CD, DVD) then locate and restore the SYSTEM file. All in all your servers down for about 5 minutes.
Dave