Here in the US, you can't really arrest someone for selling gold in-game -- it's against Blizzard's Terms of Service, so they can ban you from the game or even file suit against you, but it's not actually illegal. But in China, under communism, things are apparently a little different. Two gold farmers have actually been arrested by the government for "unfair revenue distribution" -- apparently the two had a disagreement about how to distribute the over $200,000 they had made from selling gold in World of Warcraft.
Word is going around that "unfair revenue distribution" is the actual charge in the arrest, but it sounds like they just had a financial disagreement, so we really have no idea what they'd be charged with. Unfortunately, China isn't exactly forthcoming with how its legal system actually works, so who knows what's really happening here.
Their operation also sounds interesting as well -- they had been going for about seven months, and had a crew of 20 PCs and 20 employees. There's little chance that an arrest like this will make much of an actual difference in the game (and there's no way an arrest in China will set a precedent in the US), but it is an interesting case that we'll follow if we can.