This may be obvious to some people but it wasn't for me so let me just say it.
If you select "Install Parallels Tools" from the menu bar after you've started up a Parallel's Boot Camp session, and nothing seems to happen, check your My Computer folder. What I found was that Parallels mounted the Parallels Tools installer to a new drive letter, but for some reason didn't run the installer. Double-click on the drive and the installer should start up.
Hope this helps
If you select "Install Parallels Tools" from the menu bar after you've started up a Parallel's Boot Camp session, and nothing seems to happen, check your My Computer folder. What I found was that Parallels mounted the Parallels Tools installer to a new drive letter, but for some reason didn't run the installer. Double-click on the drive and the installer should start up.
Hope this helps