I used to be an EMT-B in NYC for a private company called Metrocare Ambulance Corps. The company was the emergency responce service for Madison Square Garden and Yankee Stadium and so people would often volunteer for those duties. I first thought that this was a good idea and could be fun being a sports fan, but it wasn't what I expected. Usually, if you were assigned to the MSG unit, you would be either running around the arena responding to people getting hit by flying hockey pucks (before they put in nets) or other drunk patrons or sitting outside in an ambulance just waiting. Yankee stadium assignment was even worst, just think dozens and dozens of foul balls flying into the stands per each game including batting practice and 76,000 people amongst at least half of them who had too much to drink. I would have rather have had a regular 12 hr shift. Well, on that note you might want to call the private ambulance companies in your local area. I know that in NYC when I got my certification, there was such a huge shortage of EMTs that they would hire you and train you once you got your certification at a private company. To get a job working for FDNY or a hospital ambulance crew, you would have needed experience and still those jobs were very hard to get.
Good luck.
dmitri