Here is the best guide I've seen so far for track day n00bs. Essential Reading. Seriously. If you've ever even considered taking your car out on the track...this is for you. Lots of pretty pictures and diagrams.

PDFs in two parts:

http://gvc-bmwcca.org/drivingschool/...hronicles.aspx

...And yes, this post absolutely belongs under Performance Tuning.