pointing my android 2.2 browser to html5test.com, tells me that the video element is supported, but none of the listed video codecs... seems a little pointless to support the video element but no codecs??? unless there is something wrong with that test page.
however, i did find the same kind of situation with the audio element: the element is supported, but no audio formats. see here:
http://textopiablog.wordpress.com/2010/06/25/browser-support-for-html5-audio/