The same way that you can submit and google site map for your site you can also specify a google video site map. It can be as simple as listing which pages contain playable video, or something more complex as is shown below (taken from [google.com...]
Once you have created your video Sitemap, you can submit it to Google using Webmaster Tools.
Example sitemap:
<urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9"
xmlns:video="http://www.google.com/schemas/sitemap-video/1.0">
<url>
<loc>http://www.site.com/videos/some_video_landing_page.html</loc>
<video:video>
<video:content_loc>http://www.site.com/video123.flv</video:content_loc>
<video:player_loc allow_embed="yes">http://www.site.com/videoplayer.swf?video=123</video:player_loc>
<video:title>My funny video</video:title>
<video:thumbnail_loc>http://www.site.com/thumbs/123.jpg</video:thumbnail_loc>
</video:video>
</url>
<url>
<loc>http://www.site.com/videos/some_other_video_landing_page.html</loc>
<video:video>
<video:content_loc>http://www.site.com/videos/video1.mpg</video:content_loc>
<video:description>A really awesome video</video:description>
</video:video>
</url>
</urlset>
As with other google site maps, once you have something ready to submit you can do so through the web master tools.
For more information check out the google video blog entry [googlevideo.blogspot.com...]
