Michael Deluca the emailiac as I like to call him, has apparently mentioned that Sean Bean will indeed play Boromir. The news is on Cirdans LOTR page, hopefully more news to follow as I check up on this.
TheOnering.net has just learned, through Sean Bean’s agent that he HAS been cast as Boromir, this is official confirmation! TheOneRing.net just placed the call a few moments ago to the UK. 🙂