Animoto has a special section for real estate (http://animoto.com/business/realestate) which specifically targets real estate professionals. The service has a free and paid subscription model. Unfortunately, you will probably find that the free service will not be sufficient to produce high enough quality videos but it's a good starting point to experiment with this service.
Once you create a video, you can choose to download it and then use the downloaded file to syndicate your video, embed it in your listing's video or virtual tour section, or feature it on your bolog or website with MyRealPage.
As an example, here is a sample video we created from professional photos (by fotographix.ca):