Step 6: Brains!
Beacuse it uses servos, there's no need for complicated motor drivers or what-have-you. Simply hook up +3.6 volts and ground (straight from the battery) to run the motors, and hit them with a pulse-width modulated signal from the microcontroller to tell them where to go.
(See the wikipedia servo page if you're new to using servomotors.)
I cut up a piece of drilled blank pcb stuff, and super-glued headers onto it. Two 3-pin headers for the servos, one 2-pin header for the battery, one 5-pin header for my AVR programmer (which I should make an instructable for someday), and the 28-pin socket for the ATMega 8 chip.
Once all the sockets and headers were glued on, I soldered them up. Most of the wiring is on the underside of the board. It's really just a few wires.