Matt explains how to get a YouTube video onto a Wordpress.com blog.
WordPress.com - YouTube Support
It's as easy as this example he uses:
"[ youtube=http://youtube.com/w/?v=_dIya1aJJKA]"
Wordpress strips out some HTML code when you make a post, so you'll be putting all of this video embed code in your blog post, and then when you post it, it disapears.
"It's for your own good."
