I've not yet had a chance to experiment with Kaltura with students but I think it has great potential for collaborative project work.
First you need to create an account
Kaltura will email you with your login details
Then you can sign in and access your account page
Here you can either start a new video by clicking on Get a New Video Player or continue editing an existing video
It's easy to include your videos onto a web page our blog, just copy the code that is displayed under the video
Once the video is on your blog or site, you and other people can edit it from there.
If you'd like to try it out, click on the Add to the videobutton
You will find that adding and editing material on Kaltura is pretty intuitive but if you feel happier following instructions, there is a set of excellent video tutorials on the Kaltura site