CAD/CAM System

G-Simple
Completely free simple yet powerful software for 3-axis mills, use it to create G-codes for drilling, milling, engraving, tapping & pocketing.
Created by Sotiris Kontogiannis

GCAM
Open Source software for 3-Axis CNC mills. Simple interface for making holes, and sketches, which after extruded, provide the cutting paths for the selected end mill. GCAM also supports RS274X (Gerber) and Excellon drill files for circuit board milling..
Screenshot

SolidCAM
A powerful CAD/CAM system with the "Save" crippled, for those who want to learn 3D modeling and part programming for milling or turning in a Windows environment. Also download the QuickStart Tutorial for milling and turning, but, to view the Tutorial you'll need MSWord 7.0 or the freeware MSWord 7.0 viewer .
You can receive a free CD with all the software and tutorials by entering the download area and clicking the link SOLIDCAM CD-ROM.
@20MB. Screenshot. Created by CADTech.

source : www.freebyte.com