It seems many of you have being experiencing an issue with App World on your PlayBook today. We've had several forum member contact us saying they've seen the error message:
BlackBerry App World is not available in your country. Please check BlackBerry.com/appworld for updates.
The solution for this issue seems to be quite simple. If you’re having this issue, just open your device settings and change your language to something other than English, wait 30 seconds or so, and open App World again.