DraftSight is a professional-grade, open 2D CAD product for users who want a better way to read, write and share DWG files. DraftSight is easy to use and is available for professional CAD users, students and educators to download and activate for free.* Based on advanced architecture, DraftSight has a small footprint, should take less than a few minutes to download, and runs on multiple operating systems, including Windows XP®, Windows Vista® and Windows® 7. More info »
A easy and powerful 2D CAD software!!
I couldn't indicate a better AutoCAD replacement.