First and foremost you need to get an OBD-II connection that will pull the data from your vehicle. I did lots of research and wanted to find the best 'bang for the buck' setup. There are fantastic options like the DashDaq but they cost $550 and I'd rather put that into other stuff - so I found the Kiwi WiFi adapter for $60 on Craligslist - pretty awesome considering they cost $149 new!
This is a really simple setup, you plug one end into the vehicle's OBD-II port and there's a 6' cable that you can mount anywhere in the vehicle. There is a little on-off switch and the wireless component lights up when it's turned on. Basically it sets up an Ad-Hoc Wireless connection to any device with Wireless access. In this case I'm using my iPhone4.
Obviously - the iPhone needs an app to read the data - so I went with one that is actively monitored/developed called Dash Command for $49.99 on the app store.
It's a pretty cool application and monitors your car in real time! Check out the screen shot below!
There are 5 different tabs (along the bottom) but this screen gives me a good look at timing and the intake temps! This screen shot was taken on 105*F day outside, so my I/C pump is working hard to keep the intake temps to ~10-12*F within ambient temps! Much better than last month when my IATs were in the 170-180*F range!
Lots to learn from this setup as there is SO much data now, so I'll need some time to figure out all this info to make more sense of it all - but the instant data is excellent and I can't complain to have a setup for ~ $110 in comparison to the $550 models out there!