Does anyone Know php script for a Domain Name Aftermarket Auction Style Website?

I am trying to start a Domain Name Aftermarket Website.

Right now, have rmbdomains.com which lists my domains for sale and my web services I provide. I was thinking of allowing others to put their domain names for sale either on this site or starting another site.

I need a script or something that will allow possibly user accounts or an automated way allow others to sell domain names- Fill out a form with thier domain name, asking price, email, name, etc. and show up in a listing. Exactly like sedo.com. Can someone help me make a script like sedo or ebay?

I currently use Dreamweaver CS3, WAMP Server 2.0, and GoDaddy's top hosting account (if this is any help).

I know how to make simple websites, but I am very new at codes and php. I have very little knowledge on this and where to start (php, how a database works, etc.). Would someone Please Help!?