If you have a Proliphix thermostat like me (I have a IMT550w thermostat) and want a way to collect data and generate reports on the data then you should visit InThrMa. The have an web-based product that does this. They have a iPhone app as well as energy-saving features like SmartStart and Heat Pump Optimization (see Beta Labs). They also offer a free (no credit card required) 2 week trial.
I have been using them for a couple of months now.
- Proliphix IMT550w thermostat installed (eco-sustain.org)