What object is character looking at

I am trying to find out what object the character is currently looking at and the face of the object they are looking at. I will have a cross hair in the center of the screen and when they mouse over certain objects i want to be able to react certain ways.

What you want to do is take a look at the Physics.Raycast function. It basically draws an "invisible line" from a point on the screen outward, and returns the first thing it hits.