Earlier today, Apple rolled out an iOS 5.0.1 update (build 9A406) for the iPhone 4S along with the iOS 4.4.4 release for the Apple TV 2G. Now this is not iOS 5.1, it appears to be just a slightly tweaked version of iOS 5.0.1.
There are no major changes reported as of now for this new firmware build. We will keep you updated if we find out anything new about this update.
Download iOS 5.0.1 (9A406) for the iPhone 4S here.