Please don't copy threads on MacRumors, there's another thread on exactly this subject just a few spaces away from yours.
Microsoft Exchange ActiveSync support
Push email
Push contacts
Push calendar
Global Address List
Certificates and Identities
WPA2/802.1x
Enforced security policies
Extra keyboard languages including Chinese and Korean
Cisco IPsec VPN support
Device configuration
Remote wipe
Ability to view PowerPoint attachments
Mass email delete
Mass email move
Bonjour service discovery protocol
Support for SVG
Parental controls
Ability to search contacts
App Store (To manage third-party applications)
New "Calendar" menu in "Settings"
Updated calculator with extra features in portrait mode, a scientific calculator in landscape mode and an updated icon.
Updated iTunes with a new icon and reordered category icons within iTunes application.
Ability to save or open images from websites in Safari
Support for Traditional and Simplified Chinese handwriting recognition
Norwegian, Swedish, Danish, Finnish, Polish, Korean and Brazilian Portuguese language interface in iPhone.
There's probably others but this is most of them.
Oh and on June 9th Steve will probably announce A LOT more features coming with this update.
