I got a Bluetooth OBDII scanner from eBay (about $13) and the free Torque app from Google Play (their app store).
The Torque app lets you create custom panels with the gauges and graphs you want. Note that I now have a temperature gauge.
Mini DIY (added 2012-08-19)
I purchased this scanner from eBay:
V1.5 ELM327 OBDII OBD2 Bluetooth Auto Car Diagnostic Interface Scanner | eBay
I didn't do a lot of research, but for $12.49 I was willing to take a risk. You might want to order from Amazon because the delivery from China on eBay is sloooow. My laptop doesn't have Bluetooth, so I ordered a dongle so I can try out the software that came with the scanner. I'll update when it arrives. This doesn't require much of a DIY, since it was brain-dead easy.
- Take the scanner out of the package.
- Plug it into the space on left side of the fuse panel under the dash. It's near your left knee when you sit in the drivers seat. It only goes in one way, with the label to the left. It's only difficult if you try to do with one hand while taking photos and you can't see that you have it upside-down.
- Turn your ignition to the on position (accessory might work) and pair your phone to the scanner. Settings -> Bluetooth -> OBDII.
- Start the Torque app. Add gauges and graphs to your heart's content. You can define up to five screens of dials, graphs, and displays.
I upgraded to Torque Pro. The interface is better and the displays are more configurable, well worth the $4.95.