JavaScript

http://naradesign.net/wp/2007/12/12/129/

						// iframe resize
						function autoResize(i)
						{
							var iframeHeight=
							(i).contentWindow.document.body.scrollHeight;
							(i).height=iframeHeight+20;
						}	
						
							<iframe src="/florakid_lib/sub/javascript/iframe_sample.html" width="600" scrolling="no" onload="autoResize(this)" frameborder="0"></iframe>