I love to act and be on stage. I also love to dance but not sing. However, I am more amazed by the staff behind the stage. It must take lots of talents to become a director, storywriter or composer and even being able to take the camera or produce special effects through the computer. I wish I had the opportunity to learn these things.
To get started learning, There's always your local theater companies who need -- as you mention -- lots of people backstage and performing various chores to pull it all off. You might start working your way in there.
Also, when one has a little experience you might try looking in other places... example:
Media Bistro - http://www.mediabistro.com
If you are looking for a media position, here's a good place to start. Register (free) to access the job postings, then search using "freelance" as a keyword.