The language that the controllers for cnc machines use is usually g code.

How can we generate our own codes?

How can we learn the codes to make our own files?

Here are some links:

http://www.cuttingedgecnc.com/foamyairplane.htm

http://www.cuttingedgecnc.com/cncmain.htm

http://www.vectorart3d.com/index.cfm/Software.htm

http://www.cnczone.com/forums/showthread.php?t=20512

http://www.imagetogcode.com/