McRib Mystery Explained (partially)

The Godfather and I are huge fans of this mystery McDs sandwich. He also has blogged about its pork goodness/elusiveness recently. Well, NPR has researched the subject and have documented their findings in this article and podcast (its a good listen): Fan Alert: The Wild McRib Has Been Sighted
There is also google maps mashup tool (user contributions) for locating their availability: McRib Locator