Listing Project

I am looking to create a listing website, like a white or yellow pages. This will be a listing site for a specific type of person, like a listing site for Doctors, or find a plumber in your area etc. There is a site which I saw that is almost exactly what I want, with some modifications, that I can point you to. (see [login to view URL]) The site will basically consist of two parts, the ability of regular people to find a 'plumber' in their area AND for the plumber the ability to log in and change their listing. Regular free members just get their name and address and tel #. Premium members get a full page listing, people can click on and read (like their own one page web site).