If you want to know exactly what has changed or been added to Windows Mobile 6, the just released Windows Mobile 6 Product Reference Guide will be a must-read. The 61-page document covers topics such as mobile communications, mobile productivity, security features, Windows Mobile 6 brand guidelines and more in great detail.
Note: The ‘More information’ link will take you to the 12MB PDF document.
Source: Jason Langridge’s WebLog