LibreCAD is a fully comprehensive, open source, 2D CAD application. It is available in more than 20 languages and is also cross platform for all major operating systems, including Microsoft Windows, Mac OS X and Linux (Debian, Ubuntu, Fedora, Mandriva, Suse, etc).
LibreCAD's interface may seem a bit cluttered at first glance, but you will get used to it quickly if you view the very comprehensive Help documentation that is bundled with the application. The interface basically has a menu bar with a large number of buttons to enable you to add elements easily. There is also a number of panes that you can view your on-going project from. LibreCAD supports numerous formats for importing, including DXF, LFF, CXF, JWW, BMP, GIF, ICO, JPG, PNG, PPM, SVG, TIFF, WBMP, XBM and TGA, whilst exporting is possible using DXF, LFF, CXF, DDS, ICNS, PBM, PNG, ICO, BMP, SVG, TIFF, ICO and PDF extensions. 