Google Video is best compared to a sort of private version of YouTube. Each Google Apps deployment allows sharing and publishing videos in a way that is very similar to what can be done with Google Docs and Google Sites:
Any user in a Google Apps domain can be granted one of these three roles. When sending a video, an owner can choose to share it, either with a list of collaborators or to make it available to anybody in the domain. The owner can choose to allow the download of a video.
The size of a video should not exceed 16GB with Google Gears and 3GB otherwise.
The domain administrator can enable or disable the video service.