American solar energy incentive programs are increasing every year. California’s Million Solar Roofs initiative is the latest of a number of solar energy tax breaks being legislated in the US.

You can read about state and local incentives on the DSIRE database.
Here is a list of Federal initiatives from the database (taken from dsireusa.org):

Corporate Depreciation: Modified Accelerated Cost-Recovery System (MACRS)
Corporate Exemption: Residential Energy Conservation Subsidy Exclusion (Corporate)
Corporate Tax Credit: Renewable Electricity Production Tax Credit
Solar and Geothermal Business Energy Tax Credit
Federal Grant Program: Renewable Energy Systems and Energy Efficiency Improvements Program
Tribal Energy Program Grant
Value-Added Producer Grant Program
Federal Loan Program Energy Efficient Mortgage (EEM)
Energy Star Financing and Mortgages
Tax-exempt Financing for Green Buildings, Renewable Energy & Brownfield Redevelopment
Personal Exemption: Residential Energy Conservation Subsidy Exclusion (Personal)
Production Incentive: Conservation Security Program (CSP) Production Incentive
Renewable Energy Production Incentive (REPI)
Green Power Purchasing/Aggregation: Federal Government – Green Power Purchasing Goal
Alternative Fuel Vehicle Incentives and Policies: U.S. Department of Energy’s Clean Cities Program

For Canadian residents, the Canadian Solar Energy Industry Association provides a list of government incentives.