Cadalyst: Bugwatch

A monthly column documenting old and new bugs in AutoCAD and their workarounds or fixes, where available.
http://www.cadalyst.com/cadalyst/article/articleList.jsp?categoryId=3032

Autodesk, Inc.

The creators of AutoCAD. Includes the searchable support database, a download area and discussion groups.
http://www.autodesk.com/

Adee's AutoCAD Answers

Answers to Frequently asked AutoCAD Questions.
http://www.satelephone.com/~adee/aaa/

Cadopolis.com

Commercial portal for products and services related to AutoCAD, with add-ons, shareware, forums and links. [Requires Javascript]
http://www.cadopolis.com/

Autodesk Point A

A second portal by Autodesk that helps designers to locate industry resources, with additional services for subscribers.
http://pointA.autodesk.com/

The CAD Depot

A repository of freeware and shareware tools for use with AutoCAD and other CAD systems.
http://www.caddepot.com/

The Autodesk File

A history of Autodesk and AutoCAD by John Walker, the founder of Autodesk.
http://www.fourmilab.ch/autofile/

CAD Forum

Database of tips and tricks for AutoCAD, AutoCAD LT, 3D Studio, Inventor and other products by Autodesk and HP.
http://www.cadforum.cz/

Autocadzone

Free AutoCAD help and tips, tutorials and video tutorials, and student examples of 3D models.
http://www.eezylearn.pwp.blueyonder.co.uk/

Draftsperson.net

Presents material about drafting with AutoCAD. With tips and tricks, a Lisp tutorial, a block library, and information about standards.
http://www.draftsperson.net/