I would advise you to print the Umpire's Manual from the NCAA. Here's the link:
http://www.ncaa.org/library/rules/20...ire_manual.pdf
There are updates too for 2005 & 6 available online.
There's a lot of valuable information in there. I actually used it before I ever called my first college game. It's a very easy read and lots of pictures to color!
I would also encourage you to just relax, take your time, be in the right position but most importantly - have fun! We are privileged to call a fantastic game, make sure you enjoy your time out there.
(Except last night when it was about 19 degrees!! Sorry, that was NOT fun!)