Garage Sale Listing and Mapping Site

I would like to create a community website that will allow citizens to list and map garage sale. This will be a free service that will contain advertising on every screen and list/map print out. I would like each listing to be verified via email or by phone. The email will be automated and the phone a manual process. I would like an admin page that I can modify or delete a single, multiple by selction or all sale before a certian date. I am not concerned what mapping service we use, but the mapping service has to be free. I would like to intergrate it into a Wordpress Site, however, I would be OK with it being a subsite just so the color and graphics match. I would tend to think PHP, Ajax, MySql and Google API would be the best solution. However, if need I will host it on whatever kind of server is the best. I have put togather a simple PDF with some of this information. If you know of a site you could clone or an example site that you want to build it like, let me know.