1. Make sure you have copies of your EMT certification, CPR card, and certificate of completion from your EMT-B course or a Verification of EMT Status form filled out and sealed by your home state (available here) and/or NREMT.
2. Print out the EMT reciprocity application (from above) and fill out all appropriate sections, and attach a $150 check made payable to the Commonwealth of Massachusetts.
3. Put together the packet, mail it to MA OEMS:
Massachusetts Department of Public Health
Office of Emergency Medical Services
99 Chauncy Street, 11th Floor
Boston, MA 02111
4. You will (eventually) be given an authorization to test, after which you can schedule an appointment with PSI exams to take your written examination. Naturally, this carries another ($55) fee.
5. Be patient, OEMS isn't known for its efficiency.
Note: please be sure to include all necessary documentation requested in the application including a check for fees