As I mentioned before, Michael Robertson (of MP3.com fame) is backing development of online software tools using AJAX. He previously had announced ajaxWrite and ajaxSketch. You can get notification of new programs from the ajaxLaunch.com announcement site.
The latest title is eyespot:
Shoot, Mix, and Share your Video.
Use the eyespot Mixer to edit and combine your videos, music and photos online! Share your video and mixes with the world for Free.
I haven’t tried it (I don’t have any video to edit), but it sounds pretty cool to be able to edit simple video in your browser. If you’ve tried it, be sure to leave a comment.
Note: AJAX is a development process/technique. You can learn about it on Wikipedia.