http://www.registeredoffenderslist.org/
Visit that site, and be warned... they're all too close (theres one 3 blocks away from me, and an elementry school... yuck)
Teach them that the dangers of strangers, and how to get out of a car trunk (ie taillights/trunk relese.
Teach them what they should do if they're taken into a car, in the passengers seat (grab keys, make them hit somebody, honk horn... whatever they show in the videos)
Dont let them get into the short short/skirt style thing... That includes your son
Keep them dressed modestly.
This is all stuff I learned throughout my public schooling, ask their school if they show videos or whatnot on that.
Good luck
~Nate