Ensure that Outlook 2007 is enabling the iPhone to connect with it. Try these steps if the sync is not working with Outlook 2007.
1. Open Outlook 2007 and click Tools > Trust Center.
2. Under Categories, click Add-ins.
3. Under Details, look for iTunes add-in under Inactive Application Add-ins.
4. In the Manage box, click COM Add-ins, and then click Go.
5. In the COM Add-Ins dialog box, select the iTunes sync add-in.
6. Click OK.