There's rather a lot of this I disagree with, but it doesn't really matter - the phrases "the Goldman Sachs" and "The Ben Bernank" alone are enough to make me crack up these days.
This is great:
About Guitar Amps - Guitar Amps Terms Explained
Just quoting here for posterity, in case the page goes poof. Some pretty basic stuff, but also some pretty good explanations of less-basic bits as well.
I have been using this method to teach my guitar students for the past 8 years. I find that in the beginning when they are learning theory related to the guitar or bass its best to remove the circle of fifths to the equation till they can get a grasp on the basics of scales and modes.
Below is...