We're still waiting for some completely official word on the matter, but it looks like a Sprint exec has let slip the carrier's launch details for the BlackBerry PlayBook. While the post has since been removed, Sprint Marketing Director Gerald Evans revealed on his personal blog earlier today that the WiFi-only, 16GB version of the tablet will be hitting Sprint stores on Sunday, June 5th for the usual $499.99. Unfortunately, there was no mention of the carrier's 4G version which, last we