Hugh Piggotts plans 'How to Build a Wind Turbine' are good.
Look also at his website: scoraigwind.com
There is a lot on our website: otherpower.com (look over the wind section)
Here are the basics: otherpower.com/bottom_line.shtml
Ed's website: windstuffnow.com
There's lots and lots of reading to do out there! The 'links' pages on Hugh's site is a good one to get lost in.
Hugh's book 'Windpower workshop' is excellent, unfortunately the publisher doesn't seem to keep up with demand and everyone is chomping at the bit for the next printing! (they really don't have their act together unfortunately - it's a great book, maybe you can find a copy on ebay or amazon.com)