Here’s where you’ll find all of my LEGO model instructions. These consist of step-by-step images, LDraw files or both.
For editing or viewing the LDraw files it you’ll need LDraw and I recommend MLCad as the editing GUI. Also, once you have those, the excellent LDView app is great for quickly browsing and viewing LDR files.
You can get all these apps (and more) from here: http://www.ldraw.org/Downloads.html
Click on the child links on the right (under this link to this page!) to access the actual instruction pages.