Seamless Integration with Outlook
Google Apps Sync for Microsoft Outlook allows you to use Microsoft Outlook 2003, 2007, and 2010 effectively with Google Apps. Google Apps Sync for Microsoft Outlook provides seamless integration with your Google Apps email, contacts and calendar.
Alternate Outlook Integration Options
Alternatively, you can access your Google Apps email from Outlook using the IMAP protocol. For more information and step-by-step instructions see the supported IMAP client list.
To configure calendar synchronization between Microsoft Outlook and Google Calendar, use the Google Calendar Sync tool.