I've heard of it, but never seen it. I suspect it's an "urban legend" related to the virus warning hoax. But it may exist. (The fact that even I've never seen something doesn't refute its existence. :)
>Isn't there a Budweiser Frogs trojan floating around somewhere, though?
Rich Addison, Micro Vane, Inc., Kalamazoo, MI
Relax, don't worry, have a homebrew.
- Charlie Papazian, The New Complete Joy of Home Brewing