SRD:Light Crossbow

Description
You draw a light crossbow back by pulling a lever. Loading a light crossbow is a move action that provokes attacks of opportunity.

Normally, operating a light crossbow requires two hands. However, you can shoot, but not load, a light crossbow with one hand at a –2 penalty on attack rolls. You can shoot a light crossbow with each hand, but you take a penalty on attack rolls as if attacking with two light weapons. This penalty is cumulative with the penalty for one-handed firing.