Though I'd share this online Camera Simulator site with other on AP. The neat thing about it is along with the usual descriptions of the terminology like , and it has a Flash demo in which you can adjust these settings and see the result on the same example photo. It also has a feature to link the to the - when in this mode changing the also changes the , like when you set your camera in AV mode. The same applies if you change the , will change - like if in TV mode. Changing the also makes the example shot grainy.
Down the bottom it has a and as you play with different settings you see the effect on the , under exposed, correctly exposed and over exposed. Throughout all of this the image change to reflect the settings.
The little diagrams to the right show a graphical example of the , and . You see the changing, there is a test button for , try it on 1/8sec and try it again on 1/4000sec.
I've shown this link to several work mates just starting in photography and they found it a big help.