Thanks for this excellent plugin ! Works perfectly with WP 3.1.X.

I’ve only one comment about it: it’s hard to find. I’ve been looking all over the internet for something like this. It’s just when I decided to develop it by myself that i’ve found it !

Maybe you could add a few keywords to the plugin’s page 😉 I often used keywords like “WordPress Youtube video css custom style” in my searches.
A screenshot with the example of a frame around a video could also be useful, making the utility of this plugin easier to understand.

Thanks again ! And if you wonder about the result, check it out: http://uppix.com/f-frame4e03f844000baac7.jpg 🙂

http://wordpress.org/extend/plugins/oembed-styling/