- Ldraw.org has 3D Lego modeling software you can download, as well as libraries of virtually every Lego part ever made. Very cool.
- The Art of LEGO Design An article by Fred Martin, originally written for the magazine, The Robotics Practitioner. This article contains a lot of low-level LEGO tricks and explanations that may help you in your designs. Also, please visit Fred's web site.
- Lego User Group Network (LUGNET)This is a web-based message board of all kinds of Lego users and enthusiasts. Some are collectors, some are into particular product lines like the Lego train sets, and some are into Lego robotics. The site is very well organized and well archived.