Sven Rafferty has posted information from one of his "sources" who claims that an update to iPhone's mail app will integrate Microsoft Exchange DirectPush support. Not only that, but this feature upgrade will also enable OTA (Over-The-Air) syncing of contacts and calendar events as well.

In effect the iPhone will interoperate with corporate Exchange accounts just like a Windows Mobile device. Sounds great, but this is still rumor (Read: unconfirmed).