Most developers I've talked to don't really suggest big property tax breaks for wind. Net metering allows small renewable power generators to sell electricity back to their utility at the retail electric rate. 30 states now have a net metering law of some kind in place. This is usually, but not always, done as part of a larger electricity restructuring law. They also specify what type of resources qualify for the program.
Many utilities offer green pricing programs.
The number of green pricing programs has been increasing. PDF documents require the Adobe Acrobat Reader in order to be viewed properly.