Walt Mossberg denies having any specific knowledge of the 3G iPhone's release, despite matter-of-fact comments to the contrary last week.
But Walt notes that in the clip, he's making an aside during a larger point about data networks, and says that in any event, he doesn't know if it's correct. So where'd it come from? It's a ballpark estimate, he says, based on... the same speculation the rest of us are seeing.