Most of what I write isn't relevant to Instructables. My main blog is here: biodieselhauling.blogspot.com
**End Digression... On to the Good Stuff**
Most solar systems installed on houses are hooked up to a special electric meter which can both draw on the grid and feed back into it - which makes the meter run backward.
That is pretty cool!
However, these systems generally run from around $25,000 to $50,000 and take anywhere from 10 to 20 years to make up for their up front cost in reduced utility bills.
My solar photovoltic system is independent of the utility company. It cost me about $400 (unless you happen to live in an RV, boat, or cabin, it will cost you just a little bit more)
I still use traditional electricity for some things, so I still get a bill each month, but it reduced my electric bill by almost $15 a month, which means it will pay for itself in a little over two years.
Step 1: Reduce demand
My previous instructable is a great place to start: http://www.instructables.com/id/Not-your-average-save-energy-advice
These are steps you should be thinking about doing anyway, but it becomes all the more important when doing a solar electric project.
This is because solar systems (whether grid-intertie or not) are priced by the kilowatt. The fewer you need, the less your system costs, and the sooner it pays for itself.