The story lies in the Sony Xperia S support forums. The initial post was in response to a customer query, but left everyone -- quite rightly -- reason to get excited. Now though, it seems the gentleman in question -- going by the name of Marcus -- has "mixed things up" with the dates for the rest of the Xperia line.
Before we're too hard on Marcus though, he still says that the Xperia S will be updated during Q2. The latter part of Q2 to be more precise. By our maths, that basically says it'll be late June rather than early June. It's still coming, and it's still coming in Q2. It's just going to be an extra couple of weeks potentially before it lands. We're all human, and Marcus has had the decency to own up to an honest mistake, and to apologize for it. Can't say fairer than that.
via Xperia Blog