98 Escort electrical problems

I have a 98 Escort Lx w/ approximately 80000 miles. Over the last couple of months I have notice a dimming of some dash lights. It would be dim for a while and then get back to normal. I didn't think much of it then. In the last couple of days as I drove, all of my lights would dim and the seatbelt signal light and another signal light would flicker on and off rapidly and erraticly. Finally, today all of the dash lights faded, the spedometer went to zero, and radio died and everything that ran on electricity in the car faded out and lost nearly all power, but at the same time the engine was running fine. So I decided to head home as long as the engine was still running. On the way back home, the engine started to hesitate, which I assume is due to the same electrical problem. I just about made it home and the car completely died at a stopsign. No power at all.
A month back I had the car in the shop for other reasons, and they told me that the serpentine belt was showing some wear and should soon be replaced. I'm guessing that this is related to my problems. Or has my alternator gone bad?