it is a bunch of weekenders who get together in parking lots and race. Courses are set up with cones in parking lots and you race against the clock. The are like time trials on coned courses in huge parking lots. The are several clubs in virginia that run autocrosses.
www.vmsc.org
www.tidewatersportscarclub.com
www.odr-scca.org
The SCCA runs autocrosses nationally. Solo 2 is another name for autocross. go to
www.scca.org
This page will tell you about autocross, too:
http://www.vmsc.org/autox101.html
hope this helps.