As I noted in a recent post, Objectivist had written a critique of libertarian arguments against intellectual property. At the time the article was not available online, but it has since been posted: Don't Steal This Article. I have not had time to reply in detail, but let's just say, for now, I think the critique--while a decent attempt, about as good as you can do given some of Rand's premises--is confused and utterly unpersuasive.