There are a lot of ways I suppose. Gamerprinter has recently gotten into publishing his works and has been working with a publisher. If you search out his posts you will see he has been keeping us updated so you can kind of get an idea.
You might also like to look at this post, How-to-get-commissions-and-get-paid-to-map.
If you want to self publish your work you can do that but then you have to worry about selling it, obviously. There are some sites that allow you to do that. Kickstarter comes to mind and there was a Gamer website that RecklessEnthusiasm mentioned some time back. I can't seem to find it now but it allowed you to sell your own game on their site.
As this is something I'm still digging in the dirt about hopefully some of the more accomplished ones around here can add more.
For now I have been working on building up my body of work so I have something to show when I get around to doing this myself. My thought is that as you get better known it should open more doors to you. We'll see.