I wrote a small post on Cakemail blog about using iframes, here an excerpt and a link to the full article.
If you are a front-end developer that need to use a cross-domain iframe, you know pain. You could write a nice bit of code and get it working on firefox but it would crash on ie. You would think that would be easy – facebook, twitter and all the others cool kids are doing it! Well, not quite.
We had 2 problems to solve based on embedding. One was to change the iframe height dynamically (no way in hell were we going to save the iframe height in a database). And sometimes, depending on what functionality our users embedded in their website, we needed to actually redirect the parent page.