Boring. Second time this was posted; dangerous only if you are dumb enough to download and install it without checking it out first. Some PC people are so desperate for Mac users to start sharing their misery that they latch on to stories like this as if they were gospel.
I didn't see the first post but it looks like there are plenty of "dumb" Mac users just like the "dumb" PC Users. Social Engineering works no matter what the platform.
Ed has posted three stories on this, and between the Forums and the other information, this is real enough for those affected.
Posting this doesn't mean that I am anti-Mac. You do what you want and think what you will.