similar to trip advisor

I am looking to develop a site similar to trip advisor, where people can review and rate a range of service providers. The site will require location search facilities, as well as 'type of business' - not unlike the yellowpages.com. Under each business category I would like the Best and Worst rated business to be highlighted. I would like the site to have banner advertising opportunities - have not decided on the mix of display or pay per click advertising - on each page. I would also like the number of visitors calculated on the home page. All copy supplied. Design desirable (but not imperative). I would later be looking to make the site iphone app compatable. Many thanks