Putting your video on your site as well as spreading it on video sharing sites is the best idea. When you upload it, be very specific with your tagging and description to make it easier to find, (don't forget to make your company name or site URL a tag too).

Another advantage of video sharing sites is that you create a profile page, where you give your company extra exposure and your site earns another link.

Here's a very useful listing of video sharing sites I used to upload our commercial:
http://ovguide.com/generalvideo.html