As part of my research of several CNC platforms, including a CNC plasma table, CNC lathe and a CNC mill, I have come across the following software components that may be useful in building a tool-chain.

Firmware and Software

Hardware information

 

Raspberry Pi

The folks at Protoneer have come up with a nice guide for CNC control on the RaspberryPi: http://wiki.protoneer.co.nz/Raspberry_Pi_CNC_-_Quick_Start_Guide