LibreCAD, Open Source 2D-CAD
LibreCAD is a free Open Source CAD application for Windows, Apple and Linux. Support and documentation is free from our large, dedicated community of users, contributors and developers. You, too, can also get involved!
Our Wiki : http://wiki.librecad.org
Our Forum : http://librecad.org/cms/home/get-help/forum.html
Our Blog : http://blog.librecad.org/
Our Code Repository : https://github.com/LibreCAD/LibreCAD
Video Tutorials: http://www.youtube.com/results?search_query=librecad (Big thanks to the tutorial authors)