CP1 is a conversational machining program written by a summer intern at NIST (need to ask Fred Proctor what his name was), and modified slightly by Ray Henry, Matt Shaver, and Lawrence Glaister (http://wiki.linuxcnc.org/cgi-bin/wiki.pl?LawrenceG
). It allows you to create g-code files for rectangular and circular pocket milling, bolt circles, hexagonal and rectangular arrays of holes, and "bezels" whatever those are. Hint: expand the window size to see all of the options.
CP1 can be downloaded here:
Some example screens how it looks like