NREL’s site to let you test whether it’s worth it to install the panels.
DOE’s site about incentives, administered by NC.
From there, it all depends on the state in which you live.
First, read this. Read it all. Yeah, I know it’s a lot of text. I know it’s not sexy like solar panels. But it is the best distillation I’ve found, anywhere, for any price, of the hundreds of tips and bits of analysis out there. Realize that every dollar spent on CFLs saves 50x as much CO2 as a dollar spent on solar panels. If you’re not willing to pay the premium for one of these, you shouldn’t install solar panels.
Then, check out this site.