the course you will have to take is called "firefighter 1". the first step is just to go down to the station and ask to volunteer....you will probably have to fill out some application paperwork and wait for a background check (this was the case for my first aid squad). you may or may not have to interview with the membership committee. after that at the monthly board meeting you can be voted in (again, this is just how it works for my first aid squad). you're a probational member for a period of time while you learn the ropes (squads and FD's are very conservative/traditional, you'll be lowest on the totem pole for a while). you can then plan to go through fire school, and once you pass out of there you're certified to do more things (try to do fire school over a summer).
hope that helps!