How do I implement activesync protocol in iphone app? Any advice, any docs and tutorials are well come.
I have read the Exchange ActiveSync and iOS 4 Devices from apple. Is there any real docs for this?
It is hard, but not impossible to write an app which communicates via exchange active sync. The link to the Exchange Server Protocols in Jons answer contains a document named MS-ASWBXML. You have to write an encoder for wbxml on your own and the document describes clearly the needs. Additionaly I recommend strongly this document: http://www.w3.org/TR/wbxml/
If the low level is working, you have to implement the EAS-protocol on top ob wbxml, which is not trivial, because of bugs in the documentation, different behaviour of different protocol versions. It will be a lot of trial an error to examine, why the exchange server does not understand your requests ;-)