Google rolled out a beta service to search TV programming yesterday, and Yahoo added a tab on its home page leading to its video search engine. Google's TV search allows users to search for a term to find the TV shows in which it was mentioned, which includes a still image of the video and closed-captioning text of that segment of the program. Users cannot yet watch a clip of the video. You can see it in action at https://video.google.com.
Yahoo, on the other hand, searches for video clips on the internet, allowing users to view the clip when found. Both search engines will likely add new features once legal hurdles are cleared and business models are in place. It is always interesting to see search evolve, but I for one, am glad that I don't have any video-related sites to have to optimize for. At least...not yet.