If you have ever wondered how much it would take to go solar, FindSolar is a site that will give you a rough estimate (for US residents).
If you are in the mid west, the cost to install a roof mounted photo voltaic (PV) would be typically around $40,000 - $50,000. A solar water heating system would be around $3000. These states provide no rebates or incentives.
New Jersey appears to be the most solar friendly state. The state provides rebates to the tune of $20,000 (and more) !. Cost of a PV system is also slightly lower.
The blue states in the Northeast, West and NorthWest all seem to have state rebates upto $10,000. Almost all the red states I checked, did not offer any state rebates.
The numbers I have listed in this post are just estimates at best. The site will give you a county and utility company/usage specific figures. You can even get a list of the local contractors. The feature I liked was the break-even and ROI analysis. A New Jersey resident can have a break-even in just 1 year. If you are in a red state, chances are the numbers are not pretty!