Great finds so far, please keep 'em coming -- I have a feeling this will turn into a useful thread!
It's also great to attach screenshots to the things you find. I'll add two for the programs you found already -- please consider attaching new ones for new things you find.
Xtimeline (
http://www.xtimeline.com):

"When we developed the timeline tool, our friends thought of many ways to creatively use the timeline. Some of them thought the timeline could become a great public service, a resource for history education and for debate over current issues. Others wanted to create biographical timelines for celebrities and their scandalous relationships. The ability of these timelines to entertain and educate convinced us that other people would enjoy our timeline as much we do. And that's how xtimeline came to have a home of its own."
Dandelife (
www.dandelife.com):

"Dandelife is a place for you to record the events of your life, past and present, public and private. Have you photos and videos online in different places? No worries. Like you, your Dandelife is ultimate mash-up. Live well - we're listening!"
Similie (
http://simile.mit.edu/timeline/)

"Timeline is a DHTML-based AJAXy widget for visualizing time-based events. It is like Google Maps for time-based information. Below is a live example that you can play with. Pan the timeline by dragging it horizontally."
As cettolox said, this one isn't a hosted solution, it's a library you can use on your own site.