In the Windows Phone 7 chat with Microsoft Sr. Product Manager, Augusto Valdez we learn that the email and calendar programs will support the standard iCal format. While older versions of Windows Mobile always supported the ability to send meeting requests and manage attendees, they generally only worked with Exchange users in your domain. With the standard iCal format, meeting requests should now work across all of the different email and calendar programs that support iCal. This is great news for sharing your calendar events with others!