iOS6 comes with a great new feature you can use to password lock an app or only a part of the app so you can hand over your iPhone to other people without worrying they will do or find something you don't want.
Let me show you how to add a Google account to a Samsung Galaxy SIII so you can read you Gmail email, download apps from the Play Store and synchronize you Google Documents.
If your phone doesn't want to boot up again after the update, it gets stuck in a black screen, follow this tutorial where we root the Galaxy SII with Odin and put an official Samsung Android 4 ICS on it.