Category - Home Selling Questions - General Home Selling FAQ's
Yes. A sign is one of the most effective and least expensive ways to advertise your home for sale. People drive by areas they want to live in so having a sign is extremely important. As a FSBO (for sale by owner) it's probably the best way to advertise your home.
References
Courtesy of HomeOwners Advantage and link that to their entry in the wiki which is at HomeOwners Advantage