I haven't done any road racing or HPDE (high performance driver education) yet, so I won't try and answer all your questions myself. I came across this FAQ while I was looking for something else. There's some good info here.

http://www.unsage.com/faq.htm

good stuff. ill be doing atleastone HPDE school this year. my friend is an instructor at Summit Point and Virgina International Raceway so ill prolly end up doing them at either of those tracks. if money and time allows, i'll def. be doing as many as possible. i just cant wait:D