Open your iTunes software on your personal computer.
Power on your iPhone and plug it into the computer using the USB cord that comes standard with all iPhones when purchased.
Click on the iPhone icon in the pane on the left of the main iTunes window.
Click on the "Info" tab, and then select "Google Contacts" from the drop-down menu that appears.
Enter your Gmail user ID and password when prompted, and the software will export your iPhone contact into your Gmail account.
You can use iTunes to upload existing Contacts from your Apple device to Gmail. Only the following information can be uploaded:
- People's names and job titles
- Company names
- Email and postal addresses
- Phone numbers
- IM names, including the type of service
Other information, like custom ringtones and photos, are not uploaded. Please sync them to Outlook first.
Once you've checked that your contacts are available on the web, disable iTunes Contacts sync with Google. If you don't do this, you'll see duplicate contacts on your phone.
- Connect your iPhone, iPad, or iPod Touch to your computer using the USB cable.
- Open the iTunes application.
- Select your iPhone and click the Info tab.
- Check the Sync Contacts with option and select Google Contacts from the drop-down menu.
- Click Configure and enter your Google username and password.
- Press Apply to sync your device with iTunes.
Use the SAME Google account with the Nexus One when you get it that you exported them too and it will all sync nice and easy.
One thing to note, to make life easier, create contact groups in the GMail WEB application (from a Desktop Machine). This will allow you to select which groups sync, which don't and some widgets that show contacts are easier to use when using groups.
Hope this helps!