IOS 5

iOS 5 is the 5th major release of iOS for the iPhone, iPad, and IPod Touch. The version is currenty available and can be downloaded at iTunes.

New Features include but are not limited to:
 * Notification Center
 * iMessage
 * Newsstand
 * Reminders
 * Integration
 * Can play content while device is synching with iTunes
 * Group by Album Artist option in Music
 * Shortcut to Camera from Lockscreen
 * Able to flag emails
 * Reading List in Safari
 * Search within a web page (iPad 2 only)
 * Pivate Browsing
 * iCloud
 * PC Free
 * FaceTime without a SIM (iPhone only)
 * Hide keyboard (iPad only)
 * Tabbed Browsing (iPad only)

Trivia

 * Initial release on iPhone 4S
 * iPhone 3G and 2nd generation iPod Touch aren't supported
 * iPhone 4, iPhone 4S, iPad, iPad 2, and 3rd/4th generation iPod Touch are fully supported