What is New in iOS 6

Apple had just announced details of its upcoming iOS 6, but the final version will only available to the public later this year. 
Here are the highlighted changes:

Apple Maps

No more Google Maps. 3D and turn-by-turn navigation

Siri

More languages (Mandarin, Cantonese, Korean and more), new iPad support, more 3rd party apps support, car voice control

Facebook

Facebook integration includes Safari, Photos, Maps, Siri, Calendar, Contacts, Notification Center, App Store

Photo Streams

Share photos via iCloud, like photos and make comments

Passbook

New app for boarding passes, movie tickets, retail coupons, loyalty cards, all in one place

FaceTime

FaceTime over cellular networks

Phone

Decline a call and reply with text message or set callback reminder, new Do Not Disturb mode

Safari

Sync pages opened accross iDevices with iCloud Tabs, offline reading with Reading List, upload  photo/video from Safari

Read more from here: http://www.apple.com/ios/ios6/