Resources to understand robot locomotion and Gait functions
Here's one source - Tilden's BEAM/Solarbotics stuff tends to be low-power, low-tech, but the flip side of this is that it is simple. I believe he even had a six-leg gait generator built using a single hex-inverter chip. A quick googling produced

http://faq.solarbotics.net/nvnet.html
http://faq.solarbotics.net/FAQ.html

Also, Valentino Braitenberg's "Vehicles" is a completely amazing book where the starting point is a simple reflexive control system and as the book progresses, increasing complexity is added. Google for 'braitenberg vehicles' and you will also find a simulator related to the book.

http://www.amazon.com/exec/obidos/ASIN/0262521121/johnwiseman