From what I've read - accusations from a victim who has already had a number of successful cases. So it's an accuser with some credibility.
So you'd go to a movie directed by Jerry Sandusky (assuming a quality movie with actors you respect)?
Sure. If you're going to boycott the movie, then I assume you will find out where he eats, shops, gets gas, etc. And boycott those places as well, right? Crap, he likes tacos? Guess I'm done eating Mexican food.
My watching the movie can't enable or prevent Singer's actions. If no one went to see it, maybe you'd damage Singers payroll...along with hundreds of other innocent people who have a stake in the film. Heck, you might not even get your message out - maybe low ticket sales are viewed as a lack of interest in the source material. People need to think a little more about the outcome of their actions before doling out punishment. And this is all assuming he did anything wrong - Singer is being viewed as guilty until proven innocent.