If you have Microsoft Outlook, it can use several methods for syncing your contacts with your iPHONE; this guide doesn't cover that.
If you use iTUNES whether or not you also use Outlook, it too, has many ways to work with your contacts.
But for me, both iTUNES and Microsoft Exchange have tended to mess up my contacts as much as automate the sync process, so I have found another, and what I believe is a safer way for Windows users to keep contacts in order.