In the new update they added:
- Japanese language support for Siri
- Photos can now be deleted from photo stream
- Camera shortcut now always visible on Lock Screen for iPhone 4S, iPhone 4, iPhone 3GS and iPod touch (4th generation)
- Camera face detection now highlights all detected faces
- Redesigned Camera app for iPad
- Genius Mixes and Genius playlists for iTunes Match subscribers
- Audio for TV shows and movies on iPad optimized to sound louder and clearer
- Podcast controls for playback speed and a 30 second rewind for iPad
- Updated AT&T network indicator
- Addresses bugs affecting battery life
- Fixes an issue that occasionally caused audio to drop for outgoing calls.
iOS 5.1 Lock Screen cammera shortcut.