National Sex Offender Registry
This blog is normally pretty light-hearted, but I came across this link and thought it a good idea to post this:
http://www.familywatchdog.us/default.asp
There are links to tips to keep your kids safe, products (like safety watches), amber alerts, etc.
The site is pretty well-designed and their use of the Google Maps API showing the proximity of sex offenders to an arbitrary address is certainly an eye-opener.