According to this post on the Wordpress developer sites we are finally going to get a automatic system for handeling Vimeo/Youtube and maybe other embeds directly in the write module. All you need to do is to paste the video link on a blank line in the write new content page. Wordpress will handle the rest. You can get the same functionality with plugins today, but native support is ace.
I`d reckon we will be able to adjust the convert function to our HTML5 needs in our own functions.php file.
This article was updated at 5:54 pm on October 20th, 2009 by Kenneth Dahlstrøm Nordahl