Your iPhones contacts can be synched with your computers contacts though iTunes. You can set this up by plugging in your iPhone, Opening iTunes, clicking on Contacts, and then checking the box next to sync.
Unfourtunately, you can't, you will have to reenter the data.
you can not reverse the sync
You can sync your iPhone to iTunes to transport music, pictures, videos, etc.
You can sync your iPhone to the Nook app including your bookmarks and other pages.
This page explains How to Sync iPhone to Outlook http://www.sync-iphone.com/contacts-calendars-email/sync-iphone-contacts-to-computer.html
In iTunes, click on your Iphone and mark the box to sync addresses. At next sync it will sync. If you have a MobileMe subscription it can automatically sync over the air without user intervention.
you need itunes, and sync it on itunes (it says sync ) at the bottom right
Cheat it! If you have an Yahoo account, there's a way to link all your contacts from Outlook to Yahoo and then sync with iPhone automatically... Sign up Plaxo for free, install outlook add-in and make it sync with your yahoo account. Once it is done, you now can make iTunes sync straight with your Yahoo! Another solution is to register on Funambol and use the utilities they provide... one of them is to sync with outlook. With Funambol you can update your contact using the iPhone's Safari. If you do not want to install any additional software, follow these instructions, search for "sync iPhone with Yahoo" for info. But if you don't want to sync with the cloud, then another option is third party software like Akruto, which can sync Outlook with iPhone.
Sync it to iTunes.
No
Sync your iPhone to iTunes on our computer
"Once you plug into iTunes, there should be a folder on the top that list: Music, photos.... one option is contacts." There is no such folder in the top list, but click on your iPhone in iTunes and go to the Tab called Info. There you can select services like Gmail, Windows Contacts etc. to sync your iPhone contacts. Be careful, this will sync in two directions. Therefore make sure not to delete existing contacts, but to merge contact information on your iPhone. If you simply want to copy your contacts from your iPhone to the PC (into iTunes is not possible) you may use a backup software or app, allowing you to export contacts.