"While we've become smarter at discovering this information on our own, we'd certainly appreciate some hints directly from webmasters," says Google's Michael Cohen, Product Manager for the Video Search Team.
On top of supporting the aforementioned formats, Google has also kicked off a series of Webmaster Central Blog posts, which are aimed at giving tips to get your videos indexed. One subject they have already discussed is the submission of video sitemaps.
Webmasters can submit their video sitemaps to Google via Webmaster Tools. The video sitemap uses the Sitemap protocol, but it also has additional video-specific tags. The details on how to create a video sitemap are explained here.
Keep an eye the Webmaster Central Blog for further tips in the near future. You can see what Facebook Share and Yahoo SearchMonkey RDFa look like here.