After 4 months testing wait is over now, Apple has finally released iOS 5 final version for iPhone, iPod touch and iPad. iOS 5 is compatible for iPhone 4S, iPhone 4, iPhone 3GS and 3rd and 4th generation iPod touch as well iPad 1 and iPad 2.
iOS 5 has more than 200 new features like iMessage, notification Center, Twitter integration, Over the air software update and many more.
Its highly recommended backup your device before update..
Here are direct download links to iOS 5:
iPhone 4 GSM
iPhone 4 CDMA
iPad 2 GSM
iPad 2 CDMA
iPod touch 4G
iPod touch 3G
Apple TV 4.4