Is there any tool that can summarize Registry and File differences between two VMWARE Windows XP images?
I'm not aware of anything specifically for VMWare images, but if you can start up the VMs then why not use standard file & Registry diff tools?
For example, RegShot will allow you to take a snapshot of Registry and filesystem information, and compare it with another snapshot taken from a different machine.
Assuming the VMs you want to compare are powered off, I would try using the VMware Disk Mount utility to mount their virtual disks and then use diff or your favorite file comparison tool on them. There is a little tutorial on using the utility here: http://www.petri.co.il/virtual_mount_vmware_virtual_disk_without_vmware.htm.
I can suggest you Ashampoo Uninstaller
It can create shanpshoot of registry and file system, export it to various formats. 2 different snapshots can be visually compared within it, or you can even create installation out of it.
Superb tool, I use it for years even before Ahsampoo bought it, to make portable tools.