http://www.fairfaxcounty.gov/consumer/licensing.htm
i think it's $35 to get a license. also, i believe it's a $1000 fine if you get caught without one.
solicitors licenses are generally issued re: home solicitation sales act.
Section 31-2-1. - Licenses required; surrender of revoked or suspended licenses.
It shall be unlawful for any canvasser, peddler, or solicitor to engage in such business or act within the meaning and application of this Chapter within the County without first obtaining a license therefor in compliance with the provisions of this Article. However, a person may obtain a promoter's license in accordance with the provisions set forth in Section 31-2-4 to sponsor an arts and crafts show where peddlers, itinerant merchants, or solicitors may engage in business without obtaining separate licenses for each peddler, itinerant merchant, or solicitor who participates in that show. Any license issued pursuant to this Chapter shall remain the property of Fairfax County, Virginia, and upon written notification from the Director, any person who has been issued a license which has been suspended or revoked shall surrender and return that license to the Department. (2-18-70; 1961 Code, § 18-3; 16-73-31; 22-84-31; 10-93-31, § 1.)