Lancelin 'Back Beach' is the most accessible, and generally worth a look (but not good on a low tide). First left as you go into the reduced speed zone, and then next left into the car park. Shifty beachies across about 800-900m... You can drive on the beach if you have a 4WD.
Other breaks are off-shore reefs etc... Edward Island, Lancelin Island... plus another couple of others...
Cops the wind early... any South in the wind and this place feels it - hence it's popularity with the windsurfing crew...