Copyright issues:
If you're looking for some education on this, pick up a copy of "Copyright law for the Graphic Designer."

Now, as an artist who has done media work (such as yours) and one who has run an art show for a local science fiction convention for the past seven years, what I know is this: Yes, you can sell your stuff. Folks have been doing it for an age. There's two ways to go about it, however.

DO NOT - I REPEAT - DO NOT sell your originals short. That is, if you decide to sell your originals at all, which you really don't have to do. I know a couple of local artists who keep their originals, and sell prints at $45 apiece.

If you want to feel a little better about "infringing" on the copyright, you really don't need to worry. Something tells me Joss Whedon would be perfectly fine with the marketing of imagry that came from something he created. gorram fox isn't worried about being overtaken in terms of revenue on fan-created artwork either. Cozen is right about that. In short - the copyright Nazis will not appear at your door. If anyone had a problem with your stuff, the "cease and desist" letter would be in your hot little hands already.

Another way to feel better about it is to go with a limited run. You don't have to go out and do the big old lithograph printing. I did a laser print my Mal portrait for a charity auction on the night of the BDM premiere and it came out beautifully. It also sold for $50.

There's others here who will have better information - I'm just giving you the viewpoint from the fan-art side of the verse. Once you get famous, of course, you'll have someone else to worry about it for you.

I too am unsure of the legalities involved. However, I'm sure that any profit you may make selling your interpretations of the Firelfly/Serenity 'verse would be but a pittance relative to the marketing value inherent in keeping the franchise in the common consciousness. That is to say, the value of your work is, in part, measured as free advertising for those who hold the rights to the Firefly television series and the movie Serenity.

The labour and materials you provide cost F*x and Vivendi nothing. So I, for one, see nothing wrong with you hopefully making a buck or two while keeping the franchise alive.

Yeah: and the art is cool! Good work, and thanks for your efforts!

I love your work and think you would have lots of buyers. I think if its your interpretation of something its ok. But if your worried about copyright there is usually a copyright council in each country you can counsult.

The one here in Oz has lots of fact sheets available on the web. Maybe wherever you are too.

I love your work and wish I had some talent. I don't know if that would be a copyright violation or not. Ask someone who sells the Blue Sun stuff, unless they have permission I would think that would be more of a violation than drawings. Could be wrong though.