I've been retrofitting a DynaMyte 4400C vertical mill with Mach3 (see thread link in my sig), they seem pretty good machines. I've been looking for a DM3000 but never found one, unfortunately.
Good to see that others are interested in this machine. I posted some old brochures from Dyna that I had laying around. They are also in the thread below.
Chris.
List of parts sources for CNC builders - http://www.CNCsources.net
Dyna Mechtronics 4400C Conversion - CNC bed mill w/toolchanger to Mach3 conversion - http://www.cnczone.com/forums/showthread.php?t=50787