Tracking Code Generator web application

We need a competent web developer to build us a simple but good-looking application to be hosted on Rackspace. The application generates a code, based on the input of certain user-generated parameters. It is fairly simple stuff, but we want it to look good for one of our customers. We have written the app in Excel right now, so it should be fairly straight forward to rewrite it in whatever you think best, for deployment in HTML.