Microsoft has released the final version of Activesync 4.5 for Windows XP that includes major support for Exchange Activesync using Desktop Passthrough

Here are the new Exchange Activesync related features:

Customers using Windows Mobile 5.0 devices with the Messaging and Security Feature Pack and synchronizing to Microsoft Exchange Server 2003 Service Pack 2 or Microsoft Exchange Server 2007 will benefit from the following feature enhancements included in ActiveSync 4.5:

-Direct Push Technology
-Local Device Wipe
-Certificate powered authentication to Microsoft Exchange

Customers using Windows Mobile 6 and synchronizing to Microsoft Exchange Server 2007 will benefit from the following feature enhancements:

-HTML formatted email
-IRM protected email

Support for Outlook 2000 has been removed.

This version is only for Windows 2000, XP and 2003. For Windows Vista, you can download the Windows Mobile Device Center here

Download Activesync 4.5 Final here