Although you can set up Parallels to use your Bootcamp installation, expect some problems. These from my experience with v3186:
1. After setting up the VM with Parallels everything seemed fine at first but when I logged back into Bootcamp, I kept getting a Windows File Protection error. Apparently Parallels Tools had changed some vital Windows settings and I got prompts to insert my XP disk, which seems to restore the windows file. Upon rebooting Windows in Bootcamp, the error was not repeated. However, every time I ran Windows in Parallels, the Bootcamp got corrupted again. Every single time.
2. Parallels prompts me for a passwords both to launch the Windows VM and to exit. I have never used a program which asked me for a password to exit! This gets really tiresome.
3. The first time I launch Windows in Parallels after starting up OS X, once I get beyond the password nag, Parallels goes through the "Parrallels tool is initializing" process (which it does every single time) I hear this is a normal process for using the Bootcamp Xp installation under Parallels. It takes almost 1 minute. (this is probably when it installs files that corrupts my Bootcamp partition). Anyway, this first VM session ultimately works OK. However, if I quit Parallels, and try to launch the VM again, I get a "Unable to open disk image boot camp!" error. I have to reboot OS X in order to be able to get back into the VM again. Meanwhile when I launch Bootcamp next time, I have to go through fixing the corrupted file (see No 1 above)
I have unistalled and reinstalled Parallels and Parallels Tools multiple times with no difference to the above. Also updating to 3188 has not made any difference.
I wonder what other people's experience has been. I'm using a brand new MBP 2.33 with 2GB RAM and 512MB for my VM.