I've never actually watched it (hence why it's still pristine) however I know there's a torrent of it floating about somewhere where someone's made it digital. I can't remember where I got it.....fanedit, myspleen any of the myriad other geeky websites I used to frequent......no clue.
I do, however, know that they got James Earl Jones back especially to record the new dialogue, just for the game.
Edit: Something tells me it was daveytod.
A quick google search also tells me it was indeed Dave Prowse in the suit, and that they also had the same Cinematographer that did the films. What an effort for (what I hear is) a crap board game.