This is a good primer on residential solar.
Basic overview provided by the U.S. Dept. of Energy.
Look up your state and see all the state and Federal incentives available for renewable energy investments. Great resource provided by the North Carolina Clean Energy Technology Center.
Estimates the amount of electricity produced by a solar energy system annually, broken down by month, based on your geographic location and the basic design of your proposed system. Also provides the dollar value of that energy based on the current rates of your provider. Excellent tool for assessing the financial return on your investment. Developed by the National Renewable Energy Laboratory.
String Sizing Tools
Sizing your solar panel strings correctly is a key part of planning a dependable system: many equipment manufacturers offer online sizing tools that do all the math for you: