What can I do to fix the dispenser in the front of my fridge?
When you push the levers in to dispense water/ice, do you hear the motor running (but nothing comes out)?  If so, then it's probably a supply problem (iced up line, etc).  If not, then it's likely an electrical problem.  Most likely a fuse or a bad relay.

To get into the unit, you would (usually) need to remove the whole plastic panel on the inside of the door.  The screws are usually hidden underneath the seal that runs around the edge of the door.  Your user manual might have some useful information as well.