Napatsakom, I just watched your film from 11.11.11 and really enjoyed it. You did a great job telling the story and opening the eyes of many! I hope you can join us again on 12.12.12. Do you have anything in mind as to what you would like to film that day?"
You have some excellent questions and I don't have all the answers yet. As far as I know, as many students or teams of students as you like may submit videos. I don't know the time limit (or MB limit) but I recommend keeping them short - under 5 minutes each, say. I don't know what file formats are accepted, but they are using the YouTube engine for their video upload site, I understand, so I bet that whatever YouTube's technical requirements are, the requirements for this project should be the same. Hopefully the Educational Toolkit (be sure to sign up for one!) will give us some specific answers. As to what software to use to make your videos, I think anything you are comfortable with is fine. Even better... don't 'edit' at all. Choose 3-5 minutes of raw footage that best shows whatever it is you want to show us! I think anything added - fancy cuts, background music, titles, etc., will only make the video unusable for use in the larger project (a professional film or films). Instead of using titles, there will be a field during the uploading process to help you describe in text format what the viewer is looking at.
I hope this helps! As soon as I know more I will share immediately.