Develop Facebook application

I would like to have a facebook application developed, that allows facebook page admins to easily create a custom tab for their page. The admins should be able to add this application/tab to their page and then have two major fields: Field number 1: Content for non-facebook fans. Here admins can add HTML, CSS, Javascript and other code, which should be visible to non-fans. Field number 2: Content for fans. Here admins can add HTML, CSS, Javascript and other code which should be visible to page fans only Other than that, the administrator should be able to preview both contents from field number 1 and number 2.