Transmission Temperature Gauge

For those who do not have a transmission oil temp gauge on their TV but would like to be able to check the Transmission temp under adverse towing conditions, here is a possible option to installing a dedicated transmission oil temperature gauge ($??).
For $300 and a LapTop Computer (or PalmPilot), you can buy a gadget to connect to your TV computer diagnostic connector. It lets you monitor 100's of TV parameters besides the transmission temp. You can have your co-pilot watch the readings or you can simply log the data to the hard disk for later viewing. Your TV must be 1996 or later offering OBD II diagnostic data. This may be less expensive than installing a dedicated temp gauge. It has a nice GEEK factor as well :-)
Mine is used on 2002 GM product but Ford and Chrysler versions are available too.