I've known something of this from personal experience, and I suspect a few of you can say the same. But this report by Rob Kall puts the story in the open:
FBI Puts Antiwar Protesters on Criminal Database; Canada Uses It To Ban Protesters From Entry
You can find it at http://www.infoshop.org/... or somewhere on http://www.opednews.com
I'm not copying everything. You can read the story at the link.