Timetoast is a free online timeline generator. Users can add events and timespans to create a graphic history of personal, cultural, historical or other events and share their timelines with the world. Timetoast also allows collaborative editing. It's a great tool for student presentations and projects. See my quick sample about Great Moments in Le Tour de France below:
Users can add links and pictures to their timelines, but at present there doesn't seem to be a way to directly embed videos. Another drawback is that it seems to be impossible to remove the month and day from an event, so if you're creating a timeline about ancient Egypt, for example, you had better be prepared to guess at King Tut's birthday. But aside from these small quirks, it's a versatile and easy-to-use tool.