www.ldraw.org
None of this would be possible without the LDraw community...
www.technic-dialog.de
All about Lego Technic and much more.....
www.crowkillers.com
One of a few ingenious designers what Lego Technic terms.
Holly-Wood.it focuses on virtual LEGO building with the LDraw System Of Tools by providing tutorials, utilities and software add-ons.