With the Porsche club. Non-Porsches are welcome too! I've autocrossed 3 times with this club.
Come on out, I just registered REPU. It's usually sixty bucks for 9-11 runs. Run/work event. If you run your car on track you also have to shag cones so eat your Wheaties.
Orange County Porsche Auto-X homepage:
http://www.pcaocr.org/autocross.html
Create a new account and register here:
http://infoconnsystems.com/AXReg/