I just put a whisker biscuit on my bow Friday; however, it is shooting to the left and I pushed my sight as far to the left that it can go. Can you move the rest over that the biscuit sits on, if so, do I need to adjust anything else on the bow? One guy told me that I can move the rest over to the right, but I was concerned that this would affect the arrow sitting straight when nocked.

it is pretty obvious that the only thing you can do is move the rest to the right.
chances are is that the arrow is Not sitting center of the string.
one good way to tell is it will shoot even more to the left at a longer distance.

sounds like you need to move your rest to the right a little. Bigpapascout is right shoot at a farther distance to be sure then gradualy move the rest until you are centered where you want to hit. good luck

I would say you need to tune your bow, or have a good pro shop do it for you. More than likely your way out of whack as far as center shot is concerned.