The download can be found here in the Microsoft Download Center, the Windows Mobile site page is still to be updated.
Here's what's new...
Feature: A device can stay connected to cellular and wireless networks while also connected to PC. Benefit: Enables the device to receive incoming VoIP calls and MMS messages when it is connected to a PC.
Feature: Integrated Information Rights Management (IRM) activation is available from the PC.
Benefit: Provides access to IRM-protected content on the device.
Feature: You can enroll for device certificates from the PC.
Benefit: Enables Exchange Sync with servers requiring certificate based authentication.
Feature: Support is provided for HTML formatted e-mail.
Benefit: Adds the ability to configure HTML e-mail sync settings and sync HTML formatted e-mail from Outlook and Microsoft Exchange.
Feature: Microsoft Windows Installer technology provides a seamless installation process.
Benefit: Improves the setup experience.
Feature: The application has been visually updated.
Benefit: Modern graphics complement the visual style of the mobile device.
Feature: An integrated troubleshooter utility is included.
Benefit: The utility scans your PC and device to identify problems that can affect the use of your device with the PC.
Feature: You can log on to Microsoft Exchange using just a user name and password.
Benefit: E-mail IDs are supported in the username field for hosted users, which makes it easier to log in.
Feature: Overall stability has been improved.
Benefit: Enhances the reliability of connecting devices and syncing.
Feature: Improvements to PIN lock have also improved the interaction between the PC and the device.
Benefit: Provides a better and more secure experience.
Feature: USB support has been improved.
Benefit: ActiveSync 4.5 provides the fastest USB transport between your PC and your mobile device to date.
Feature: The user interface and new partnership wizard have both been enhanced.
Benefit: Easier to locate key features, access the most important configuration settings, and configure the device upon first synchronization.
Feature: More robust synchronization with Outlook is provided.
Benefit: Synchronization with Outlook is now more reliable.