One of the improvements in Parallels v6 is better support for Time Machine, if you are using a Disk Image based backup (eg. Not using a Boot Camp Partition).  Sadly, there doesn’t appear to be any backup improvements for us Boot Camp users…

According to Parallels:

One of the ways to back up your virtual machine(s) is to use the Mac built-in Time Machine Utility; it’s one of the easiest ways to keep your computer safe.

Parallels Desktop 6 for Mac includes improved integration with Time Machine.

When backing up the virtual machine, it will only backup the recent changes (the latest snapshot), but not the whole virtual hard drive.

Thus, the backup process will take less time and use less space on your Time Machine storage device.

To enable improved integration with Time Machine, please go to Virtual Machine Configuration, choose Options and hit Backup.

Select “Optimize for Time Machine” in SmartGuard menu.

If you do not want your virtual machine to be backed up by Time Machine, you need go to Virtual Machine Configuration –> Options –> Backup and put a checkmark on “Do not back up with Time Machine”.

via KB Parallels: Backing up virtual machines with Time Machine.

I have examined my Time Machine drive, and the Boot Camp partition doesn’t seem to be backed up in any way, which is what I expected. So these changes appear to be directed only at the Parallels disk image(s), which is what is implied by the application, but the knowledge base article doesn’t state.  The Knowledge base article can be read to imply that all versions of the virtual machine are backed up, implying a Boot Camp solution…