If you've been using an iPhone, iPad, or iPod Touch for a a couple of years, you have probably done a couple of upgrades of iOS. Do you know the whole history? If you don't, you should read this book.
Now that iOS 6 has been released read all about the new features. These include Passbook, Apple Maps, Safari changes, Guided Access, and much more.
finally ios6 is released i was waiting for it