www.calclub.com/
www.sfrscca.org/
here are the web sites for SCCA in Cal. You can do a two day super school and get a racing license for SCCA. This does require an SCCA legal racecar, drivers and saftey gear.
With this license you can apply for a NASA Comp license and will have to prove your ability in a DE setting. You may get passed the first time or it may take a few events to get approved. This is usually the fastest way to go racing.
The NASA method does take longer. But you can do most of it with a street car.
So there are benefits to either system.
At NASA you will have the support of the 944 group if that is the class you are looking to get into. You can start with a street legal 944 or buy a race ready car. It is cheaper to buy a racecar in the long run. The racecar can be street legal so you could drive it to the track.
Do you have any track experience?