Ldraw.org - A freeware program which can create Lego models in 3D. Learn about LDraw and download related software.LDraw Launcher - DOS graphic front-end for LDraw.
BlockCAD - 3D fun drawing program uses Lego like blocks. Provides a gallery, downloads, and instructions.
Paul Gyugyi's LDLITE Version 2.0 - A program that displays 3D Lego models. Platform, release dates, and installation information provided.
LeoCAD - A CAD program that uses bricks similar to those found in many toys. The program can import LDraw files.
Jacob's Lego Toolbox - An overview of Lego related tools, including LDraw. Mostly for making building instructions.
LDraw and LEdit Tutorial - Learn how to use LDraw, a popular Lego CAD program for DOS/Windows.
The LDraw model repository - Building instructions for official models (in LDraw format).
LEGO CAD: Simple Machines - A computer-based educational LEGO building kit, designed to teach concepts in basic machines.