The hardest part of this repair was determining where (controls, motor, belt or transmission) the problem was. I could see little pieces of rubber from the belt beneath the motor pulley, but the machine is 20 years old and some wear is to be expected. Since the belt was still intact and neither frayed or cracked and since I didn't know what the original dimensions were and since the machine was still able to agitate, I could only identify the belt as a possible source of the failure to spin.
After determining that the transmission and motor still moved freely and that the motor still powered up when the tub had filled, I removed the old belt looking for product numbers that I could either order from via an internet search or at least cross-reference to another part number. That turned up nothing definite. Apparently the original belt company went belly-up some time ago. Then I searched on the part number for the washer and hit pay-dirt ... several places carried parts for the machine. But I could only actually FIND the belt on two of them. APP was the less expensive by $7.00, so they got my business.
All that was really needed was 5 minutes of thinking and testing to be reasonably certain that the problem resided with the belt, then to find and purchase the belt, wait 3 days for delivery and then another five minutes to replace it. It took me longer to open the panel (at first I didn't see the front mounting screws, so I loosened a side panel by mistake) than it took to make the actual repair.
I took away a star because, while APP was the least expensive source for the belt, I still feel like I paid $56 (plus shipping) for a $10-$15 part.