It’s always good to have your contacts synced with the cloud because it makes them portable and accessible from multiple devices. You can use MobileMe or other free services to sync your iPhone contacts. Windows Live Contacts is one of the free and popular services provided by Microsoft. Many people like me need to sync their Windows Live Contacts with iPhone. If you have Microsoft Office Outlook 2007, you can do this by following these steps:
Go to http://downloads.live.com and download Windows Live Essentials installer. Run it and at least check Microsoft Office Outlook Installer and click Install.
After installation, run Microsoft Outlook 2007 and in the menu, first click Outlook Connector and then click Add a New Account
Enter your Windows Live ID details and name you want to appear in the receiver's box. Click OK
You need to restart Outlook. After restart, please wait while it sends/receives all the data.
Then go to Tools>Account Settings and click Data Files Tab
Sync your iPhone and you are done!
While syncing if you get “OutlookSyncClient”, you can try these fixes