iOS 4 offers over 100 new features. Here is a description and demo of one of major new features, the new Mail app. Mail gets some attention in the way of a unified inbox. This allows users to see all email from all inboxes on the iPhone in one screen. Also added, you can setup more than one exchange account to the phone, which is really cool for people looking to use Google Sync with multiple Gmail accounts or Exchange and Gmail w/ Sync. Also added is a new organize by thread feature, and an ability to open attachments with an app of choosing. Finally, our biggest gripe, Mail now offers fast inbox switching to get between account inboxes easier/faster.
iOS Features Video Playlist
iOS 4 is a free upgrade for the iPhone 4, iPhone 3GS, iPhone 3G, iPod Touch 2G, and iPod Touch 3G. An update for the iPad is expected this fall.