Jquery Login Modal Window

I currently have a login window that drops down from the top of the page and it works in all browsers but IE8. When IE8 is used, the window does not slide down to allow user input. For this project I need somebody to create a login popup modal window that is compatible with all browsers including Ipad, Iphone, IE6 IE7, IE8, Safari 5+, Firefox 3.6+, Chrome 8+, Opera 10+. Instead of the login window that slides down. I would like to use the same pop up found on the newsletter subscription form with the addition of an X button to also close the modal window. You can see what I am referring to by downloading the attached file [login to view URL] and for the LOGIN window that currently does not work in IE8, you would click "company assets" and the newsletter subscription popup is accessed by clicking the grey envelope next to the twitter/facebook icons. Essentially all you are having to do is reformat the login form so that it looks like the newsletter subscription form (with an X to close it as well) and work in ALL browsers.