Simple PHP form script

This should be a very simple script for a php programmer to build. I need a web based script. The user goes to a URL with a web page containing the script. They'll see a web page, and embedded in that page is a form. The form says "Enter your email address here: " and then give a space to enter their email address. It will then add the email address to a URL that I want to have the ability to change, but it would be in the format: http://variabileURLthatI [login to view URL]@[login to view URL] The someone@[login to view URL] would be changed to the email that they enter, and then it will open that url in their browser when the click the enter button. That's all there is to it. Allow me the ability to add that script to pretty much any web page.... and we're ready.