Hey, there's not really any "video" field type in MF, but you can get
pretty close by using a Multiline text, and then taking advantage of
Wordpress AutoEmbeds:
http://codex.wordpress.org/Embeds. You can then
embed, say a youtube clip by simply putting something like this in the
content:
[embed width="640" height="480"]
http://www.youtube.com/watch?
v=VIDEOID[/embed]
If you need your own movie file, try installing
http://wordpress.org/extend/plugins/vipers-video-quicktags/ which
allows some other file types too.
Eventually, we'll make some proper "Video" field types, but the
priority right now is Custom Post Type support :)
Good luck!