I've written about XTimeline in the past because I find it to be a great service that is very accessible to high school students. Using XTimeline students can collaborate, just as they would when making a wiki, to build a multimedia timeline. Timelines built using XTimeline can include text, images, and video. XTimeline will accept dates in A.D./B.C. format.
TimeGlider offers some nicer layout features compared to XTimeline, but is not quite as intuitive to use as XTimeline. The layout features that I like about TimeGlider is the ability to stagger or indent events below each other in a sequence. TimeGlider also makes it easy to display the relative importance of an event by increasing its size in comparison to other events on the timeline. Like XTimeline, TimeGlider accepts dates in A.D./B.C. format.
Time Toast is quiet easy to learn to use. To add events to a timeline simply click on the inconspicuous "add an event" button and a simple event box pops up in which you can enter enter text, place a link, or add a picture. Time Toast does not have the more advanced editing options that XTimeline and TimeGlider offer. What it offers instead is ease of use which makes it a suitable choice for students in elementary school or middle school.
TimeRime allows users to create timelines that include text, images, audio, and video. One of the better features of TimeRime is that you can have more than one type of media for each event on your timeline. TimeRime users can also select which media type they want as the feature piece of each event. As we've come to expect with any web 2.0 tool of this type, you can embed the timeline in a blog or share it via email.
Dipity is a great timeline creation tool that allows users to incorporate text, images, and videos into each entry on their timeline. Dipity also incorporates a mapping feature which allows users to place a Google Maps bookmark related to the topics the timeline covers. Like most good web tools, Dipity has a collaboration option and has multiple options for sharing products publicly or privately. Each entry to a Dipity timeline can include multiple types of media which allows users to add more detail and information than can be included in a traditional timeline.