The video that immediately came to mind when reading this question is http://www.youtube.com/watch?v=DolFKeFTVQI
If you go to Pebber Brown's youtube channel, there are literally 85 videos that have been uploaded under the catagory "scale systems," including those that are more basic, but that one specifically I recall doing a great job of showing how to start simple, and then progress on from there. (Ok, watching through it again, it may be quite confusing if you don't even know the major scale yet, but still a very good video in terms of concepts even if you don't understand all the musical terms).