Check out some the posts from ZORTNESS, like this one:
http://www.twowheelfix.com/showthread.php?t=237
It's a good idea to take a fuel Can.
Chairs, Shade, Snacks, lots water, change of clothes, more water, sun glasses, towel to soak in ice water for when it gets real hot.
Check the threads, lot of the stuff is covered.
Here's a good page with info.
http://ti2tt.com/trackdayinfo