The BBC has a series called The Conspiracy Files.  It covers all your favourites: Princess Di, plus upcoming episodes on the Oklahoma City bombing, weapons inspector Dr. David Kelly and (wait for it) ... 9/11!!

Unfortunately, Elvis and UFOs seem to be passé.

There's a conspiracy quiz plus articles on why we love a good conspiracy theory and the roots of such theories.

Say, why do you suppose the Beeb is really looking into this topic? I have a theory ... :^)