I'm a freelancer on oDesk.. I am registered at freelancer.com as well, but odesk (in audio case) works better for me.
I found that the hardest part is to be hired for the first time. But when You are, the next interview will come quicker

And job by job it should become easyer to get a job..
BUT
It's hard to compete with people from India or Philipines.. They can make the job for way less price.. And sometimes clients give such budgets, that i even stop believing in that

5$ for custom music peace! Man...

But sometimes there are some really good deals available to apply.. So i believe it might be hard to live out of those pages, but who know.. Maybe somebody are living out of that.. Anyway it's still worth to add some $$$ to Your wallet isn't it??
Just if You're new, be patient till You be hired for the first time.. It took ~2 months or so for me to get hired for the first time.. Everybody wants people with an experience (i mean experiene on odesk let's say).. If You have no working history, You need to have some patience
All in all, trying is free right?

Go for it!
P.S. I've recently hired a person myself

I was in need for a custom postcard and greeting card design.. So i used odesk for finding a person to do that.. Prety good option!
Good luck
(Edited on 2013-02-22 16:21:24 by softpiano)