Tracking Devices for Convicted Sex Offenders

Dear President Bush & Congress,
I would like to bring forth to you an issue that seems to be plagueing our communities alot these days and a possibly a way to end this problem.
In recent days more and more of our children are coming up missing or murdered at the hands of convicted sex offenders. We as american's understand that the goverment has some programs in place to protect our children however these programs and stipulations do not seem to very effective (exe.Megan's law .. requiring sex offenders to register with local law enforcement)
Today I would like to bring forth an idea that may help our goverment get these sex offenders under control and protect our children and our communities . We would like to propose the idea of a tracking device implanted in each "convicted sex offender" in which each each offender is given a number and implanted with a device to track his or her where abouts . Not invading the privacy of any person however thus pin pointing each offender to a location at all times. So that in the event of a missing child a system would pin point wether or not a sex offender may or may have not been in that area and giving detail reports by numbers in the system as to who the sex offender is and location in which he or she may be found.
If we can track a car for purposes of finding it, if stolen . Why can't we track sex offenders for purposes of finding missing children and other vicitims of sex offenders? And thus making convicted sex offenders think twice before they act as their ability to hide or deny would be impossible?
I would like to submit this petition to you, signed by those of us who think this would be effective and would like to see this action take place to protect our communities and stop others from becoming victims.