hm, own experience with so called bass tutor -> 1. asking what song do you want to learn, 2. checked tabs online, wrote down by pencil, 3. played it a bit. when done go to 1.
(amps we had there were everything but bass, 8 inch driver etc..)
Maybe unlucky me but after couple of lessons i quit as complete rubbish.
Since somebody mentioned S.Cowell and that kind of TV shows this always make me laughing:
[url="http://www.youtube.com/watch?v=lm_FKOEk73M"]http://www.youtube.com/watch?v=lm_FKOEk73M[/url]