I recently came across a gorgeous Flash presentation briefly chronicling the history of the universe, from the Big Bang to humanity. Check it out: Evolution - What Next? Click on the red "Time Slider" arrow to get it started, then click and drag the slider along the timeline. I haven't explored the rest of the site in detail yet, but there seem to be many more Flash animations on other topics relating to biology.
Credit to Table of Malcontents for the original link.