Suggest you start on the PCA Potomac site. Here is the link to the Autocross Home:
http://www.pcapotomac.org/pca/html/a...utocross.shtml
If you have not done autocross before, you might look at this:
http://www.tirerack.com/features/solo2/handbook.htm
Keep in mind that Solo II is the name for autocross that is used by SCCA. The procedures in the handbook above apply to SCCA events. A variation is used locally for the Potomac events.