Probotix offers several kits that add computer numeric control (CNC) to the X2 Mini Mill. I used their 3-Axis Monster Mill Stepper Motor Driver kit, plus a Ready-to-Run bundle that includes some additional components required to get it operational. For the computer itself, I used my old ThinkPad, but if your laptop is too new to have a parallel port, Probotix offers USB and PBX-RF breakout boards. Once the electronics are mounted and connected, you just need to install and configure CNC software, such as Mach3 or EMC2.
As a final step, you can fine-tune the machine and install limit switches and emergency buttons, which, although not included or required, are a safety feature that will inevitably prevent you from crashing your machine someday. Then, if you did everything correctly, you should be able to design and automatically mill your own precise and identical custom parts.