Need Help With DVD Angles Or Explanation On How They Work

[Bokken]

Okay this is something that has baffled me for some time now. I've got about 500 or more DVD's and I have never been able to change angles in any of them.
Right now I'm watching Star Wars Ep. II. I've seen this movie quite a few times and checking the disc on the computer, there appear to be 4 different angles on this disc. I don't understand why nowhere throughout the movie I cannot change them though. I thought that maybe the movie was shot through different angles but this cannot be so as on the disc there are 4 separate 1:30 (approx) movie lengths. I know that normally when you can change an angle on a DVD, a little icon should come up letting you know that you can do so but it cannot be possible that with over 500 movies and 6 different DVD players (computer included), I have never seen this icon nor have I been able to change an angle in any movie I have ever watched.
Is anyone here able to explain to me how angles work because at this point in time, different angles are just something I cannot utilise!

[Q'alooaith]

Should be a settings or menu tab before you start the film, then you can change that, you should be able to change it from widescreen to letter box, and so on.

They are not actualy filmed from diffrent angles, it's just how they clip the film for the aspect ratio of the screen your viewing on, if you've got a widescreen TV you'll want to go widescreen mode.

If you've got a standard TV then letterbox would be approriate and so on.