I hate being a blog echo chamber but yes, as you probably already know, Google has video ad units available now. There still are apparently a few glitches but it seems to work OK for me. Scroll down to the bottom of this page to see. I have the full sized unit down there.
John Chow, as always, is on top of the story, Getting Started with AdSense Video Units. He has a nice tutorial on it. If it’s giving you a problem you may want to check his comments or head on over to DigitalPoint or another webmaster forum for more info.
Anyway, I’m going to see how it does sitting way down there. They look nice but will they convert? Will people ever scroll down that far to see it? Only time will tell.
I’ve not found these ads to be effective at all. I suggest avoiding them.