Well, first off... It's after the millenium, feel free to NOT use scripting to maximize the browser, especially when your content only takes up a small portion of the page.
I'm not sure what you're getting at here. Are you saying that you want people to sign up at thedebtkiller.com and after they submit the form the username that was filled in is then used to be sent to another page?
I may just be missing something but couldn't you just use $_POST in order to get the username to use in the Location header?