It sounds like you need a fluid CSS page design, so that your page flows to fill whatever size/shape screen it is displayed on. You can find lots of posts about fluid design over in the CSS forum: [webmasterworld.com...]
Msg#: 10593 posted 1:14 am on Jul 12, 2005 (gmt 0)
Most web sites have pages with variable page lengths to accomodate the content, so only the page width is an important factor when designing.
If you are using a fluid-width design, the content will flow and fill the horizontal space. This can be a problem on short pages viewed full-screen on wide screens - it is important to consider what will happen to floated elements etc. if the page is horizontally stretched.
If you are using a fixed-width design (usually at less than 800px) then it will only fill a very small part of the screen real estate when viewed on a high definition wide screen. This problem is mitigated by the fact that the vast majority of wide screen users will not have their browser window stretched full width.