@Pookasnooks: The original question was concerning commercial games. If you're just making a game for your own enjoyment, you can do what you like.
Fan-games are a whole different kettle of fish, as they are clearly illegal - even if you draw your own sprites, it's still going to be copyright infringement. If you're trying to make any money out of a fan-game, you can expect at least an order to "cease and desist", and potentially for legal action to be taken against you (actually, that could happen even if you don't make any money, but it's less likely the copyright holder would bother).
