iphone OS 4 unveiled, shipping this summer

iPhone 3GS and new-gen iPod touch will get all the features, but some features won’t make it to the iPhone 3G, original iPhone, and older iPod touches. The biggest new feature is multitasking, which Apple says is going to be the “best” implementation in the smartphone space. App switching is activated by double tapping the home button, which pulls up a “dock” of currently running apps, and Apple claims it can do this without hurting battery life or performance for the front app. Unfortunately, this multitasking won’t be available for devices older than the 3GS and new iPod touch. Multitasking is just one of seven different new “tentpole” features, including Game Center, enhanced Mail, and more…

• Multitasking
• Folders
• Improved Mail
• iBooks for iPhone and iPod touch
• New Enterprise Features
• Game Center
• iAd

Other minor features highlighted in a slide of iPhone 4.0 enhancements include:

• File & delete Mail search results
• Search SMS/MMS messages
• Web search suggestions
• Choose image size in Mail messages
• Bluetooth keyboards
• CalDav invitations
• Larger fonts for Mail, SMS & alerts
• Cell data only setting
• Spell check
• Persistent Wi-Fi
• Gift Apps
• Birthday calendar
• Recent Web searches
• Create Playlists
• Top Hit in search
• 5x digital zoom
• Nested Playlists
• CardDav
• Tap to focus video
• Upload workouts to Nike+
• Places in Photos
• iPod Out
• Home screen wallpaper
• Search SMS/MMS messages
• Wake on wireless

For the details of all the new features, hit this link to Appleinsider.

And for the Apple Press Release, read here.