First, you need a hosting provider that gives you a database such as MySQL or SQL Server or (more expensive) offers root access that lets you install anything you want. You need a database so that you can store the information over time. Then you need someone to code the back-end scripts that handle logging and your rating. There are already packages to handle logins and other basic stuff and probably code already written for the rating part. PHPNuke and Joomla come to mind as free applications that hosting providers usually offer. However, I don't know if they can be tailored to the site design you want. A basic rating system website isn't very difficult to write, though. You'll need someone who can code in PhP, JSP or ASP and a hosting provider who supports one of those.