They are two very different experiences. Guggenheim intercuts the presentation with interviews of Gore, which makes it even more compelling.
But even if they were identical, folks should go see the movie. Paramount gives 5% of the take to the Alliance For Climate Protection. (The box office just passed the $20 million mark, so Paramount has given the charity $1 million.) It's only $1,060,000 away from becoming the #3 documentary of all time. The better the film does, the more the media takes global warming seriously, the more regular folks get active against global warming, the more pressure is put on those in office to face the problem and the more seriously corporations look for ways to be carbon neutral.
It's very important to see the movie if you can - - and see it more than once, if possible.
Moviefone.com is probably the best way to find where it's showing in your area:
http://movies.aol.com/movie/an-inconvenient-truth/24916/main