For my collaborative course in American Studies there's high demand for building interactive historical timelines into our Web site. There are plenty of instances, especially in Flash, on the Web, but I couldn't find tools to build those suckers.
After a bit of trawling, I've discovered a Java based timeline creator, freely available, from the John Hopkins University Center for Educational Resources. It's not the most visually polished thing in the world, but something's better than nothing.