Edit CNC has the features needed by CNC programmers for editing CNC G-code files, as well as all the basic applications found in a text editor. http://www.editcnc.com/
A means for analyzing and editing NC programs for machines with CNC, where changes in the G-code are immediately reflected in the graphical display. http://www.ncmanager.com/
Discriminator makes CNC files more readable for viewing and printing by allowing the user to format individual codes with any font or color. http://www.cncedit.com/
A program that simulates 2 to 3 axis CNC machines using solid modeling, with collision detection and estimation of the machining time. http://www.cutviewer.com/