Shibu to my knowledge this is not possible OTA with any mobile device. My experience tells me that the reason is that it is already difficult enough to maintain a synchronized status with the mail server on the back end...if you added the complexity of trying to sync from a local *.pst file it would make maintenance of sync even more difficult. I suppose you could try and run an Outlook(?) client on your desktop along with iTunes, have (only) the *.pst file opened in the desktop Outlook client, then try and sync via USB to the local copy of Outlook....it would be interesting to see if this worked for you...