There are many jobs in the music industry that do not directly involve the music its self. Look at the CD cover and the liner photos. That was most likely not done by the engineer or the producer. Nine out of ten times it was a professional photographer that took those images and then retouched them to make them the best that they could be.
He is not truly a musician and yet the photographer is employer in the music business, as a music industry professional.
Lots of things in and around the music business revolve around a photo or a photographer. Think of all the events that go on in the music world. The live shows, the awards shows, public appearances, recording dates. What is one thing that you can almost positively plan on seeing at every place a music event is happening? A camera with a photographer attached to the other end of it.
So photographers actually play a huge part in the music industry company. Without them there to record the things going on no one would have any way of seeing the changes that are actually happening to the artists. Lets face it; its amazing how people change when they get money. A certain Disney Diva went from a rather flat chest and some pre-pubescent funky teeth to a cosmetically nice looking late teen / early twentys look almost overnight. Without the cameras we might never have known.
But seriously, places like the various freelance places on the Internet and ones that target the music industry specifically make it fairly easy for the photographers out there that want to become involved in this portion of the industry to actually hook up with the people that are willing to give them money to use those God given talents taking pictures that will serve the music world.
What you, as a photographer, need to do is do what you can to get a portfolio of work that might be relevant to a music industry company. Go out and shoot a few local bands at some shows to give a feel for your style. Offer to help the groups out with the CD projects and even the other promo material that they need. As long as they use your information associated with that work it could easily get other bands wanting to actually pay you to do that for them and you can build up a portfolio of things to show other industry people when you approach them looking for work.