Listings via zipcodes

Looking to build have a script installed/coded on my current website ([login to view URL]) where companies can add their business listings on the website. It will be an addition to the listings I currently have ([login to view URL]). The way the listings work now, a person can add any type of listing under the category/sub category. What I want to do is under a separate page ([login to view URL]) have the saem type of setup but specifically for business listings(a business directory). It would need to have the 50 states as the main categories, and the ability for me to add subcategories(cities) for people to add their business listings. Right now these listings dont go live until approved in the back end, so it would need to be the same thing. Listings would only go live after they are approved in the back end. The original script was taken from PHPjabbers, and has been modified to include sub categories. There will also need to be and option where the person adding the listing has to put in their business address, phone number and zipcode, and an option will need to be added at the top of the page to search by zipcode and results need to be shown closest to farthest from that zipcode. The user will also have to login/signup to add their listing. Pretty straight forward. This will have to be integrated to have the same look and feel as the rest of the website. Design templates will be provided.