How do I change the belt on a kenmore dryer model 80901?

Here are the manuals: https://dl.dropbox.com/u/8010163/Whirlpool%20Dryers.zip
https://dl.dropbox.com/u/8010163/Kenmore%20Dryer%20Manuals.zip
If has run long enough to wear out the belt it needs cleaning, too. You need to totally tear it down and scrape out and wash all of the parts except the motor, which you vacuum out. You can go to YouTube to see videos on how to take it apart, but do a very good job or it will fail quickly. Get some white lithium grease and grease any bearings you find. You need to clean out a drier every two years, at least, according to the manuals.
Look at: How to clean your clothes dryer. How to make it hot again. - YouTube (http://www.youtube.com/watch?v=MMP7BW1lLs4) to see how to tear it down. Also: Mr. Appliance Tips: How to Clean Your Dryer - YouTube (http://www.youtube.com/watch?v=iBiRw-KElC4) ; Cleaning a Dryer Vent and Lint Trap - YouTube (http://www.youtube.com/watch?v=yFTZGgVisCI)
Electric Clothes Dryers (http://www.electrical-forensics.com/Dryer/ElectricClothesDryers.html)
http://fixitnow.com/wp/2010/10/09/whirlpool-dryer-model-le5800xsw3-wiring-diagram/
The job is very easy for a woman to do. Just get it out into your garage or somewhere you will have plenty of space. Pop the top and unplug the wiring harness, then you can see where the screws are that hold on the front. You will need to unplug the door switch. You should lay it on its back to make it easier to work on before pulling off front. Make sure to clean it very well and don't miss the duct on the door going to filter or the other ducts in the rear, and the blower wheel which is very, very important. A clog of cement-like lint build up can hide anywhere. Don't be afraid to take apart anything to be able to look inside and clean it. One missed place will necessitate doing all this again and no one wants to redo something. Grease all support rollers you find
With white lithium grease and reassemble and you have a new dryer. Remember, any bearings MUST be greased before re-assembling the dryer and don't miss any areas like the element housing or filter housing and air duct to drum. Mark all wires with white tape and a Sharpie. You have to unplug wires as you take it apart and when two wires go on a safety it does not matter which wire goes to which terminal as long as both are plugged onto the safety. On a door switch with a light switch in it each wire has to go back like it was originally. On a door switch with only 2 wires instead of 3, it does not matter as long as both are plugged in. If you do a thorough job you will have no problems later as long as you clean it and lubricate it once a year.