EDIT: found it - OBD2

So I have a CEL on my Mitsubishi. It has about 141K on the odo. I've read a couple of times that people have rented an electronic gadget from Kragen or Pep Boys that reads the code from the CEL. What is this called again? And I connect it from under the driver's side panel, correct? I want to give this a shot myself after calling the dealer who wants $95 just to troubleshoot. Thanks in advance.