National EMS Information System, Technical Assistance Center - Salt Lake City, UT
This file includes all of the NEMSIS-related FIPS codes for the United States and its territories. The file is a comma separated text file with the row headers included in the first row. This file is best used by importing it into a database such as MS Access, rather than MS Excel (Excel has a row limit which will prevent you from seeing over half of the states).
Windows: Simply right click on the link above and choose "save target as..." from the drop down menu.
Mac: Simply "control-click" on the link above and choose "download link to disk" from the drop down menu.