Yes, it's screen.availWidth and screen.availHeight
The screen.width and screen.height properties show you the full resolution of the display.
screen.availWidth, and screen.availHeight shows you the size of the display that is not consumed by permanent fixtures of the browser and operating system, such as the Microsoft Internet Explorer menus and Windows Task Bar.
All four properties (and others) are available on both IE and Netscape browsers. The screen object is documented at Microsoft Link [msdn.microsoft.com] and Netscape Link [developer.netscape.com].