iPhone OS 4 Beta 3 has improved the overall stability of the OS and also restores the ability to take screenshots which was missing in the earlier build. The update makes closing apps in the multitasking drawer easier by allowing you to close multiple apps at once.
The iPad has a dedicated hardware button for orientation lock as reading on the device could be quite frustrating if the device changed its orientation when you changed your angle of reading. iPhone OS 4 will add iBooks app and in order to counter the same issue on iPhone and iPod touch the beta 3 version of iPhone Os 4 adds software support for Orientation Lock.
Have you spotted any undocumented feature in iPhone OS 4 beta 3? Feel free to email us screenshots of any new features you find.[Gizmodo]