My day job is spent writing CAM software. There is a great little hacking site called Hackaday. Those two sentences may look completely unrelated but it has some great articles about making your own tools (CNC machines) to do machining.
Here is a list of CAM related articles:
How to build your own CNC mill
Make a badass CNC mill
Snowboard CNC machine
Fab@home looks really interesting as it is open-source and it is planned to manufacture itself.