dalziel

This plugin will add a noembed section no any embedded content that does not already have one. This is very handy for people reading your site in an RSS reader, as a lot of them don’t display embedded content.
Also, for any Youtube or GameVideos.com videos, this plugin will also show a thumbnail of the video. The message displayed can be customised from the options page for the plugin.
See the <a href="http://blog.slaven.net.au/wordpress-plugins/noembedder-wordpress-plugin/" rel="nofollow ugc">Plugin Homepage</a> for more information.

Noembedder

Adds noembed tags to any embeded object that doesn't have them

rtMedia for WordPress, BuddyPress and bbPress vs Noembedder