2000 Dodge Caravan 2000 Grand Caravan Speedometer Won't Wor

We just recently (last week) purchased a 2000 Dodge Grand Caravan Sport as a used vehicle, and it has worked without a hitch to this point. We parked the van last night, and when I took it out to grab some groceries, the speedometer is stuck at zero (or 1), and just a little ways from the house, the engine light came on, and there was a wierd shift issue that seemed to go away by the time I got the vehicle back home. Is this a speed sensor issue, and how do I find out?