We have been trying to predict the weather for a while now, and we've tried a lot of different forcasts. We think these are the best.
A marine forcast from NOAA, the national weather service. It is probably the most reliable wind forcast, but it tends towards the worst case senerio. Also, remember that wave hight is measured from center (the flat water level) to peak, not from trough to peak, so a 3 foot wave is 6 feet from top to bottom.
Live wind and temperature data from NOAA. The sensor is mounted on the Harrison-Dever Crib, where the city gets its water. Remember, it's three miles out and 60 feet up, so the weather there probably isn't exactly the same as the weather here.
The Weather Underground, or wunderground.com (no affiliation with the leftest radicals), is probably the best general weather forcast. It gets its data both from the NOAA, and a network of local weather stations. It also has a great interactive radar.
Sailflow, (the same thing as iwindsurf), shows a network of wind stations, including the crib, and has pretty accurate spot wind forcasts. We use the Greenwood Beach station for the forcast.