Disable iPhone Yahoo contacts sync

There is a iSync plugin for the Nokia 6300, you can find it here. Once you have synced your contact to the Address Book on the Mac you can use iTunes to sync the contacts to your iPhone.

I've used Funambol to recover\merge\backup my iPhone Exchange Contacts in the past with good results. It was a bit fussy so follow the instructions carefully with regard to what you want to sync back to their cloud and how you want contacts to be merged or you can end up deleting things you want to keep. The safest approach is to initially set it up just to back up rather than update the iPhone contacts, once you are happy that you have your contacts saved then you can use it to push the contacts back to the iPhone without worrying.