You can view and update a SharePoint Calendar from Outlook 2007. From the SharePoint calendar window choose Actions, then Connect to Outlook. Outlook will ask if it's OK to link to the SharePoint calendar. After choosing OK, Outlook displays with your personal calendar and the SharePoint calendar side-by-side. This provides an easy way to prevent potential event and resource scheduling conflicts.

Use the Overlay button to view the two calendars as one.

You can update the SharePoint calendar from Outlook either by entering events directly on the calendar or by dragging events from your personal calendar to the SharePoint calendar. Outlook will synchronize your changes so the changes you made will appear on the SharePoint site. Also, changes made to the Calendar in SharePoint will be synchronized with the calendar in Outlook.