If you sign up at http://leonardodicaprio.com/, you can access an exclusive prologue comic, called "The Cobol Job". (I think all you need to do to sign up is enter your email address)
EDIT: Site is down right now, but it worked about 5 minutes ago.
yeah i submitted my email but nothing came...i think the site might be getting too much traffic....i doubt the prologue contains any kind of spoiler....just probably explains the kind of work cobb has done prior to the movie's story