Meaning can Time Machine backup Parallels while the program is still running without messing up the backups?
*grin* Sadly, I don't the resources to find out. Hopefully by X.6 I'll have my machines to test the new OS on. I just get to wait until other people report the bugs for me.
With the way Time Machine works (backing up the entire file with every change) I would suspect that you would want to remove from the backup both your Parallels VM and any VMware VMs you have installed. I'd hate to have my VM backed up every time the data had a new timestamp from a data change. That said, I've not yet used Time Machine because Apple removed support for Airport Disks.