Milling is the process of using a spinning drill bit to remove portions of bulk material (usually wood, or a soft metal like aluminum) in a controlled way.
A large drill press with a bit more functionality. rknize has one.
Some mills are automated, and have motions that are written as a numerical program that is input into a mechatronic controller.
Currently, the only CNC mill we have access to that is not attached to a public web-based machine shop, is treble318's, of Custom Keyboard Trays. Treble's shop currently has at least one 3-axis CNC mill, a 2-axis CNC mill, and some finishing capabilities. Treble has provided inexpensive powdercoating to members as well as bead blasting.