iOS 5.1 update promised for today. The update is already rolling out to iPhones, iPads and compatible iPod touches. That brings with it a number of improvements and bug fixes, including the previously-announced Japanese language support for Siri, a redesigned camera app for iPad, the ability to delete individual photos from Photo Stream and, somewhat curiously, an "updated AT&T network indicator." What's more, as previously rumored, the camera shortcut is now also always visible on the lock screen for iPhone and iPod touch users.
Update: As a number of commenters have pointed out, it turns out that update to the AT&T network indicator is a change to display "4G" in the status bar, even though the device's connectivity of course remains the same speed as ever.