I can see that this question has been asked several times, but none of the proposed solutions seem to work for the site I am building, so I am reopening the thread. I am at
By the way, DynamicDrive improved their script to always resize even if the iframe contents change: http://www.dynamicdrive.com/dynamicindex17/iframessi2.htm
From their page:
This is version II of the original Iframe SSI script, which like the original script lets you seamlessly display external content on your page via an IFRAME. It does this by dynamically resizing the IFRAME to be the height of the page contained within it, eliminating any possible IFRAME scrollbars from appearing while snugly showing the entire external content. Think of it as SSI (server side includes) emulated using DHTML! This script works in both IE5+ and NS6+, and for other browsers, supports the option to either completely hide the iframe in question or display it using its default height.
Now, this script differs from the original in that you can load additional documents* into the IFRAME even after the page has loaded, and the IFRAME will dynamically adjust its height to fit the new document. So use this script if you need to not only display external content via the IFRAME tag, but intend to change this content after the page has loaded.