Apparently, there are a small number of iOS 5 users that have had battery life issues. Apple has been diligently working to address the issue, and is seeding their iOS 5.0.1 update to these users and a small sampling of testers. This update also brings some Siri improvements for Australian users, multitasking gestures to the first generation iPad, and a few other bug fixes. Right now, users that go into an Apple store to complain about the issue have been directed to wait a few weeks for this software update. Above is a snippet from a support email, and below is an internal Apple memo.
Share in the forums if you are one of the users getting this update.
Source: AppleForums.net via 9to5Mac