What is a "no solicit neighborhood"? Do you live in an area with a homeowners association or with CCR's?
There are no laws that prevent someone from coming to your door. You might live in a planned community that makes it a rule, but I doubt it is any type of law to prohibit people from approaching your door, if you live on an ordinary public street.
WASHINGTON – The Supreme Court ruled 8-1 Monday that an Ohio village ordinance designed to discourage Jehovah's Witnesses and others from knocking on doors to spread their message is unconstitutional.
The ordinance required groups going door to door to register with the village and receive a permit, things the Witnesses were reluctant to do. However, Monday's decision will have an effect far beyond proselytizing and will make it easier for any group to approach someone's home on a mission to advocate, as long as the resident doesn't have a "No Solicitation" sign.
http://newsmax.com/archives/articles/2002/6/17/180512.shtml