Which AVR chip are you using? Do you have a bare chip, or is it on some sort of robot controller board? Which programmer do you have?
If you're using the ATMega16 or ATMega32, you may find the docs and sample code for the SRS Workshop Robot useful:
http://seattlerobotics.org/WorkshopRobot/index.php
You'll have to modify the source code to adjust which pins/registers are used for which function (unless you're using Larry Barello's ARC board) but the code starts out with very basic stuff which should be enough to get started and customize.
If you're using another AVR chip, the basic idea is the same, but the names of the registers used for input and output may change significantly.