ModalBox/Modal Window Script Installation

I need a quick project- shouldnt take long if you are familiar with HTML/Javascript/AJAX. I need a script for a modal window popup. Similar to something like this, [login to view URL] - and honestly this exact script could be used with a bit of editing. I have very little experience with installing and implementing code of this nature. Users will click a link within an HTML page and this script will load a modal window of an HTML page over the window. It should gray out the page background. As said, very similar to the link I have supplied above. Total project shouldnt take more than an hour or two to complete. I need this done ASAP. Quick bidders who are capable will be chosen right away!