Check out AutoEditNC 3.0--NC Code Editor

<A HREF="http://www.teleport.com/~mattsonm/autonc.htm">Click here:
AutoEditNC 3.0--NC Code Editor</A> ,
http://www.teleport.com/~mattsonm/autonc.htm

I found this site interesting. And the software is free.
bill

AutoEditNC is a specialized text editor with NC code creation tools.
AutoEditNC will also simulate the movements of the machine tool so that the
student can test his or her program for accuracy and reliablility.