I'm not sure if this will help but they are located on the top side of the wheel hubs. Just follow the cables going to one of the wheel hubs. You will see where the sensor is bolted to the top of the hub. This image I found through Google.
those are speed sensors for the ABS system only. the OP is looking for the VSS (vehicle speed sensor) which is usually located on the transmission i would imagine. i have no definite clue as to the location however.