Got my letters all nice and ready to go. The bright "NO HR 669" written on them so that even if they're not opened the message is still gotten is a wonderful idea.
I also hung some fliers tonight and taped two in each of our cars (in a non obstructive place, of course) so that no matter where we are, people will see them. Tomorrow we're headed to vet's offices and rescues/shelters to hang fliers there as well.