Robot Programming : A Practical Guide to Behavior-Based Robotics by Joe Jones and Daniel Roth
I found this book to be very well written and an excellent introduction to the arbitration and subsumption model of robotics programming developed by Rodney Brooks and others at MIT. The authors were involved with the development of the very first Roomba robots at iRobot. The book won't teach you how to program, but it will give you a very good foundation in autonomous robotic behavior, which as we all know, is becoming ever more important in FIRST competitions.
I also want to echo the props for Steve McConnell's
Code Complete (either edition). It is a book that you don't need to read from beginning to end - just pick it up when you get a chance and read a chapter or two at random, and you are guaranteed to take away some useful programming insights.