I worked as a
messenger for a while, so I can relate some first-hand experience about this often-romanticized profession. I'm writing from my experience and knowledge of how it works in some
American cities; I'm sure things are different elsewhere.
Working as a messenger is a rough way to make a living. You're generally paid a percentage of the fee for each delivery made; the exact percentage varies, where the smaller "indie" companies pay better. You generally won't be paid less than minimum wage, which is critical on a slow day when you might not have many opportunities to make tags. I found that I could make a bit over the minimum on busy days if I rode like hell all day got a few lucky rush jobs.
You're expected to provide most of your own equipment, particularly the bike. This is an exceptionally poor deal for a job that pays so little. I destroyed clothing, chains, and tires at a ridiculous rate. I was theoretically covered by workers' compensation, but of course health insurance was some sort of far-off dream.
There's a kind of hierarchy among the messenger companies. Most cities have a few large companies; they're generally the only ones who will hire people who don't already have experience. The smaller independent companies may only have a few riders. They're often started by messengers themselves, and are generally considered to be a much better place to work once you've paid your dues with the big guys.
The gig does have it's advantages. Obviously, it's fantastic exercise; within weeks you'll have great legs (or you'll quit). I'd never gotten so many free drinks, kind words, or flirtatious looks from the staff of the coffee shops and burrito stands as when I walked in with a radio strapped to my chest. Compared to, say, a retail position, you have a certain amount of autonomy; if you need some peace and quiet, you can just turn off your radio.
So if you really love cycling, and don't have any better job prospects, maybe messengering isn't a bad idea. Give it a try.
I did. It's also the only job I've ever quit with five minutes' notice.