The bad news is that the videos are only available in Windows Mobile Video format which means that for the most part they only work on Windows Mobile devices. According to Sevenval's mobileWatch mobile analytics report, only about 25% percent of the video capable phones in the world can handle that format. If Microsoft is serious about the mobile web they need to support industry standard video formats like H.263 and MPEG-4 in addition their own proprietary ones. Update 21-Aug-2008: It turns out that MSN mobile video does support non-Windows Media formats. Details here.
The good news is that there are thousands of videos available. Content includes News, Sports, Music Videos and Movie trailers. The professionally made videos are current and of good quality. They are 240x340 px, average about two minutes in length and are available as high or low quality streams or as downloadable .wmv files.
Mobile Link: video.mobile.msn.com
Ratings: Content: Usability: