There is a plugin that I just installed and it worked in 3.0.1, even though the documentation shows it through 2.9.x. It was very simple, took me about 2 minutes. You can find it here:
http://wordpress.org/extend/plugins/tsl-iframe-unfilter/
You will still have the wordpress rules about filtered-html, but if you are an “admin” or “editor” you will be able to embed iframes once you have installed this plugin.
….kim
