What were the main feature upgrades for IOS4 from IOS3
Some of the main features in the upgrade of iOS4 include multitasking, airplay, folders, face time, home sharing and printing. You can get more of the features, at http://ipad.about.com/od/iPad-Tutorials/a/iPad-iOS-4-FAQ-Details-Features.htm.
Folders, new dock. BTW we are in ios 6 now
Folders, multitasking, home screen background, Game Center, and FaceTime