Alter the frame dimensions as needed. Be sure to test your creation through a range of screen resolutions. If you don't, you run the risk of things looking pretty messed up to a lot of people.
*View source: Most (if not all) browsers allow you to view the source of any HTML document. It's a menu item, usually something like View/Source. Do this and the innards of any web page is there for you to inspect. Once you learn this little trick, you'll never again have to say... "I saw (insert neat effect here) on a page and I wondered how they did that."