The drvier's sider automatic shoulder belt failed! Is there a simple way to fix this? If anybody has had this problem and fixed this yourself, please let me know how you did it!

I presume you are talking about the automatic shoulder belts that move into place along the window track when you get in. If it is only the driver's side that has failed, then I'd rule out a fuse. Do you hear the motor working to move it into place? If so, then the problem lies with the connecting pulley or gear that goes from the motor to the belt anchor. If no motor sound, I'd look for a wire break.

Older Camrys with lots of miles are having failures of power locks, windows, etc., because of fatigue in the driver's door wiring harness. Because that door is used the most, the repeated flexing eventually breaks the wires in the harness. You might be able to test this by pinching/rolling the harness where the door hinges in between your fingers. If the belt anchor moves, your problem lies there (it depends on when the actuator is activated...if it only moves when the door is closed and key on then of course you can't try this!). The harness will need to be pulled from the door, the rubber boot pulled away from the fatigued area, and the wire(s) will need to be repaired or replaced.

It's not a difficult job, but the inside of the door is kind of tight and pulling the harness out takes some patience to prevent further damage. Good luck!