Besides the Nikon D70, I also uses a Canon SD450 for quick pictures and movie taking. This is a great camera -- compare to my first Canon S100, they have come a very long way. Finally I decided to publish some of the movies that I have taken with this camera. To my surprise, the "AVI" files created by the camera cannot be edited by any software that I have, including the semi-pro software Vegas Video.
After some research, I learnt that the files created by the Canon and other similar cameras are in the Motion JPEG format, or MJPG. They are basically a series of JPEG images stored together to form a movie. This is why such a small device can capture movies -- very little processing is done by the camera. And unfortunately most video editing software does not have the codec built in to handle the MJPG format.
What to do? There are some company that sells codec for MJPG. They include:
Another slightly easier way is to use the current ZoomBrowser (version 5.5) software that came with Canon to first export the movie to a real quicktime MOV format.