Whats the difference between a Producer and Executive Producer

[jaffa]

Probably a stupid question, but when you see the credits for a movie, what is the difference between a Producer and Executive Producer?

[wcmartell]

EP is usually the money, P is usually someone actually involved in the production of the film... but there are so many P-type credits on films that it's hard to tell who actually did anything on the film. I know a producer who just introduces people... and gets a credit for that.

- Bill