Trying to save money on your monthly electricity bill? There’s an app for that.

The SunPower Monitor and SMA Solar Checker applications are two new i-wonders designed to help curious consumers calculate the performance and value of their solar power systems.

SunPower released their free application on May 18, 2009. The program gives an up-to-the-second account of how many watts your system is generating and displays detailed graphs to break down energy production and usage by day, month and year.

SunPower’s tool is compatible with the iPod touch or any iPhone version OS 2.2 or later. It’s a great add-on for homeowners with a SunPower solar system (you’ll need the system in order to use their app). In addition to checking in on your system via your iPhone, you can also view system performace data on a wireless, wall-mounted LCD monitor.

SMA released the Solar Checker on September 28, 2009. It’s a bit more detailed than the SunPower Monitor, crunching and displaying numbers on how much energy and revenue a solar power system could hypothetically produce at almost any location. Like SunPower’s app, SMA’s is free.

The Solar Checker is an all-in-one solar planning kit. It calls on many of the iPhone’s features: the GPS to determine a user’s location; the magnetic compass to recognize the site; and the inclination sensor to determine roof pitch. Once it orients itself, the app determines the amount of solar radiation available via a weather database.

Beyond assessing site-specific variables, the Solar Checker offers a set of financial tools that guide the user through a project’s estimated return on investment (ROI).