you can always visit the following sites.. sorry i dont know all the exact dates.
OC Circuit - every second sunday of the month. (http://socal.rcracing.com
Hobby People - this coming sunday, Fountain Valley (www.hobbypeople.net
4Fun Raceway and Hobbies - hesperia, also on sunday
RC Heat - Norco, July 25 (www.rcheat.com
Ko Propo Race - August 7 & 8, but entries are full.
Tamiya TCS Nationals - open entry, but TCS attendees have preferred entry (Tamiya cars only) www.tamiyausa.com
Hitec Race - not really so cal.. but its in Poway, SD area. www.hitecrcd.com
Revelation Raceway - www.revrace.com
hope that helps!