Windows Live Search seems to have introduced a video search recently. When I searched "Vishwak" the results page impressed me - you can mouse over on a result image and see the video playing in place with audio. Surprisingly it included results from Google's YouTube as well and playing it in a Live branded page.

Read the complete post at http://www.venkatarangan.com/blog/2007/11/21/Live+Video+Search.aspx