You can find your SCCA region here.
There are other sanctioning bodies that put on events like NASA and BMW CCA but I race SCCA so I can give you that. You can find the email of the region exec there and shoot them an email for general info. Or go to the website.
Make sure you've familiarized yourself with the basics, there are FAQs all over the internet, and how to prepare your car for inspection and racing (basically seat belts in good shape, battery tied down and secured, lugs on tight, nothing in the car, floor mats out, run street tires around 40 psi).
Only other advice is get out there asap and have fun.