I haven't read or watched either, but I think I would rather read the book as I hear the movie is sort of just loosely based on the book. If the movie was a documentary though!
Also very interesting [though I haven't seen the whole thing, only clips..]
The same guy who does Supersize me! has a TV series called 30 Days, where people live in an opposite way they are used to for 30 days, and one of them is 'Animal Rights
' and a hunter I believe from the southern US somewhere becomes a vegan activist for 30 days. Seemed very interesting but I can't seem to find the whole thing online.