Below are listed some useful links to websites that offer good information on building a home made wind generator
http://www.otherpower.com/otherpower_wind_alternators.html - view information on whether to use an alternator or generator on a home made windmill.
http://www.otherpower.com/bdwm53.html - view details here on how to construct a home made alternator.
http://www.otherpower.com/otherpower_wind.html - view information on several other versions of home made windmills.
http://www.otherpower.com/ - view information on this page about ordering parts for home made windmills.
http://www.mtmscientific.com/rewind.html - view the process for rewinding an alternator, and thus get 12v output at lower rpm.
http://www.lookout2000.com/windpower - view another home brewed windmill
http://www.otherpower.com/otherpower_wind_tips.html - tips for designing and building a wind generator
http://www.reuk.co.uk/Zener-Diode-Voltage-Regulator.htm - zener diode and resistor calculator
http://en.wikipedia.org/wiki/Diode - definitions of diode types
http://www.lulu.com/items/volume_66/7679000/7679760/1/print/Lessons_in_Electric_Circuits_Vol_3_-_Semiconductors.pdf - definitions of diode characteristics
http://www.newark.com/ - good site for diodes and other semiconductors