Although the task of creating animated timelines is not necessarily the most common, for the times that you have this task on your to do list, you might consider checking out Tiki Toki, a fantastic online, animated timeline maker. With several types of accounts (including a free one!), Tiki Toki makes it easy to create attractive and interactive timelines, which can display images and videos as well as text. With great integration with Flickr, Youtube and Vimeo, its easy to integrate your online media into your created timelines.
Head over to Tiki Toki and try it out for yourself. I think that you might find yourself creating more timelines, just to use this tool!