If this is just a question for interest's sake, then the other answers are great. If it pertains to something you are actually doing?
GO SEE A Lawyer. NOW.
Are you still waiting? Then I'll expand.
Go see a lawyer. Now. Don't wait, don't think. If you don't have one already, find one. Ask them to put you in touch with someone who handles business law as a job. Check his credentials, and if they look right, sit down with that person and offer them money for advice. Feel free to negotiate on terms.
If you don't trust me, and I'll admit I'm being very definite without much experience in this area, read this article, written in May 2010, by someone who's been successfully running a family business since '93.
If you are trying to run an Indie game business, you are, first and foremost, running a business. All local, state, and federal laws apply. You need a business license. Or licenses. Every business should have a lawyer and an accountant. I personally have done without having a dedicated lawyer on tap (an unwise course), but every business should have a skilled accountant.
What this means is that someone whose business comprises two people selling games where lizards in armour beat up goblins is aware he's taking a risk by not having access to his own personal lawyer at all times.
Are you a business? Don't know. If you're selling something, you could well be. Guess who would know? A Lawyer.
You don't have to pay for a very expensive lawyer for a long time, but at the very least you need to have someone available by appointment who you can run things by before doing stuff that may be legally dangerous, and who can explain to you what may be legally dangerous.
Because here's the thing. If you do it up front, then many things apply.
- You're less likely to screw up and attract the attention of the govt.
- You're more aware when you have screwed up, and what to do about it, including an existing contact you can call to help you.
- If you do screw up and attract the attention of the govt, you can explain that you tried to do everything right, and have the notes from the lawyer to prove it.
If you don't? Well, I recently discovered that if you are aware that you're not competent to handle something, and you don't seek advice, that legally means you deliberately chose to screw up. In money, that's fraud. In export sanctions, I think it's on the same scale as treason.
Regarding internet research: This blog post was written in Jan 17 2011. And the first thing it says in there? That this stuff changed recently. So it could change again. It could already have changed. Which means that if someone blindly follows this 3 years from now, they could end up having to spend some serious time explaining to besuited men that they're not a traitor, they're just daft enough to think that blog posts are legal documents.
Do me a favour for my own peace of mind. Go see a lawyer.