I've found a nice little temperature reading module that can be used to get up to 4 accurate temperature readings into AppleScript where you can pass them along to Indigo. It's called a "daq Temperature Module" manufactured by Xytronix Research, Inc. and it connects to your Local Area Network (or via the internet with proper routing). I have uploaded an AppleScript for Indigo that I've been running on both a wired and wireless LAN for the past few months. The company also makes a general-purpose Analog Interface (which is somewhat more expensive) that I plan to get in the next few months, so look for a similar script for it too. Some really nice other features of the Temperature Module are that it has a built-in web server, it can send you e-mail when temperatures get above or below user defined limits, and it has two relays that it (or you) can use to turn on or off external devices (heating, cooling, or alarms). Best of all, you can modify this AppleScript to do complicated temperature control tasks based on temperature differences, trends, etc. (stuff that is too complicated for either Indigo or the Module itself to handle). The hardware/firmware is described at:
http://www.ControlByWeb.com/temperature/index.html
Enjoy,
Chris Galfo