When syncing contacts, calendars, or notes from Microsoft Outlook, there can be issues that prevent syncing from completing as expected. Many of the issues can be resolved with the steps in these articles:
Troubleshooting iPhone and iPod touch contact and calendar syncing via USB on Windows
MobileMe: Troubleshooting Windows syncing
If you haven’t followed the steps in the appropriate article above please do so. This article provides additional steps that may allow you to sync or detemine why you are unable to sync.