[goodonpaper]

Is it possible for me to sync an unpaired iPhone with my Macbook Pro to remove the contacts, then wipe the phone & repair it - thus allowing me to resync the contacts? Bluetooth & iSync were my first port of call but has proved uniformly useless.

[babyb]

There is the option of holding down the command and option keys while connecting your phone (that will cause iTunes to open but will disable automatic syncing). Can you then choose how you sync your iPhone from there?
I've only ever sync'd my mates iPhone for him and I think the default action is to replace the contents of the iPhone with whatevers in your Address Book.
So be careful!

[Yonzie]

If you want to save the contacts in the address book, you need to sync it with you computer first, and put all the contacts in a seperate group to not mix them with your own.
I BELIEVE that it will import the contacts from the phone. ymmv. In any case, it should warn you before doing anything bad.
Haven't your friend got his contacts backed up on his computer?