Camtasia is great tool for creating computer based training videos. You can try out a free, trial version of Camtasia here.
There are several, really good modeling languages for entity-relationships.
Of course, you can always just use the universal data model and be done with it
You can download a trial version of ER Win from the Computer Associates website here.
This is a community edition that will let you have up to 25 entities. So, if you have a small data model, this will work.