What will happen if I sync my iPhone 3G contacts?

[King Mustard]

The 'Contacts' folder on my Windows Vista machine is empty and I have multiple contacts on my iPhone 3G.

If I sync them using iTunes, will my iPhone 3G go blank or will the Contacts folder on my PC populate?

I guess I am basically asked which way they sync.

I'm sure I've synced them in the past and it blank my iPhone 3G phonebook.

[ScenTiMentaL]

Well, when I added Contacts to the iPhone & synced it with Outlook it added them to Outlook & did not delete them from the phone.

[BrownGem]

If you don't have a program like Outlook, Gmail, Yahoo., MobileMe.....etc..that the Iphone can sync with..the contacts will just stay on your phone. I believe a file is created during backups (.pst file) that you can extract and save in case you need to restore so you won't lose contacts.