"Kitesurfing School"        http://tor-pw1.netcom.ca/~hungvu/kitesurfing.htm

This is a great kiteboarding site, with instruction on technique, safety, equipment, a discussion group, frequently asked questions, etc.

"iwindsurf.com"            http://www.iwindsurf.com

This is the one site to visit for your windsurfing and kiteboarding weather forecasting and realtime wind reports. 

Other good weather sites:

http://www.wunderground.com

http://www.intellicast.com

http://weather.noaa.gov/                (sponsored by the noaa, providers of the weather radio forecasts)

http://www.harbortides.com           (good tide charts)