Hey, I was looking for a way to monitor my transmission temp on my 2007 Commander without drilling, wires etc.... While I was at it, I added the Wrangler transmission temp to get a bigger audience (also other Chrysler/Dodge/Jeep models). If you have an Android smartphone (or not..see the end), you can get an OBD II bluetooth Elm327 adapter cheap (yea, it's chinese but it works...) on ebay or other sites and use a program called DRIVE from the Android marketplace (search "Transmission Gauge"). One thing though...your jeep (or other Chrysler/Dodge) has to be 2006 or newer (it uses the CAN protocol). For more info, see www.drive02.com
If you don't have an android phone: This is what I did for my neighbor.. search ebay for android phone "bad esn" 2.1 ,where you can't use the phone service but you can use the wifi to download the app from the android marketplace and use it on the phone (no monthly fee). Try to avoid AT&T bad esn because some block the marketplace for some reason.
P.s. - Yea I probaly should do this in the vendor section, but until I get rich and famous (yea right...), I'm just trying to get the word out.