Below is a list of sites with robot building tips that we like:
The Animatronics Workshop is an on-going experiment to have kids create complete robotic shows! In this site, you will find lots of information that will help you create your own animatronic shows, or better yet, start your own animatronics program at your school.
We posted some tips on the Basic Micro RoboClaw forum on using the RoboClaw with the Arduino. We are hoping to work out a low cost version of the TeleToyland Sandbox using the RoboClaw since it's a nice board. But it will be tricky since it does PID on the speed, not the distance.
Step Drill Bits are very good at making larger holes in aluminum.