Microsoft released Exchange 2007 Service Pack 3 today and this can be downloaded from the following link:
Microsoft Exchange Server 2007 Service Pack 3 (SP3) has been designed specifically to meet the challenges facing our customers and to help address the needs of all the different businesses and organizations utilizing our Exchange Server 2007 enterprise messaging system.
Exchange Server 2007 SP3 is a mission-critical communications tool that enables employees to be more productive and access their information anywhere and anytime while providing a messaging system that enables rich, efficient access to e-mail, calendar items, voice mail, and contacts.
For administrators, Exchange Server 2007 SP3 provides further flexibility with the addition of Windows Server 2008 R2 support for server roles and Windows 7 support for the Exchange management tools. These additions, along with enhancements for the advanced protection options against e-mail security threats, such as spam and viruses and the tools which help manage internal compliance and high availability needs provide Exchange administrators with the tools they need to manage their Exchange 2007 environments efficiently.
Clean installations of Exchange 2007 SP3 on a new server are possible by using this download in the same manner as you would install Exchange 2007 RTM, Exchange 2007 SP1 or Exchange 2007 SP2.
> New Deployment Options
> Windows Server 2008 R2 Support
Exchange Server 2007 SP3 supports all Exchange 2007 roles on the Windows Server 2008 R2 operating system.
Exchange 2007 SP3 provides support only for a new installation of Exchange on Windows Server 2008 R2. Exchange 2007 SP3 is not supported in an upgrade scenario on Windows Server 2008 R2. For example, Exchange 2007 SP3 does not support the following installation scenarios:
A new Exchange 2007 SP3 installation on a Windows Server 2008 R2-based computer that has been upgraded from Windows Server 2008
Upgrading Exchange 2007 SP2 to Exchange 2007 SP3 on a Windows Server 2008 R2-based computer that has been upgraded from Windows Server 2008
Upgrading the operating system from Windows Server 2008 to Windows Server 2008 R2 on a computer that has Exchange 2007 SP3 installed
For more information about the installation prerequisites for installing Exchange 2007 SP3 on a Windows Server 2008 R2-based computer, see How to Install Exchange 2007 SP1 and SP2 Prerequisites on Windows Server 2008 or Windows Vista. For more information about the supported operating systems for Exchange 2007 SP3, see Exchange 2007 System Requirements.
> Windows 7 Support
Exchange 2007 SP3 supports the installation of the Exchange 2007 management tools on a computer that is running Windows 7. Additionally, Exchange 2007 SP3 provides support for the installation of the Exchange 2007 Management Tools together with the Exchange Server 2010 Management Tools on the same Windows 7-based computer.
Exchange 2007 SP3 provides support only for a new installation of the Exchange Management Tools on Windows 7. Exchange 2007 SP3 is not supported in an upgrade scenario on Windows 7. For example, Exchange 2007 SP3 does not support the following installation scenarios:
A new Exchange 2007 SP3 installation on a Windows 7-based computer that has been upgraded from Windows Vista
Upgrading Exchange 2007 SP2 to Exchange 2007 SP3 on a Windows 7-based computer that has been upgraded from Windows Vista
Upgrading the operating system from Windows Vista to Windows 7 with Exchange 2007 on a computer that has Exchange 2007 SP3 installed
For more information about how to install the Exchange 2007 management tools, see How to Install the Exchange 2007 Management Tools.
> Improved Password Reset Functionality
Exchange 2007 SP3 introduces password reset functionality for Internet Information Services (IIS) 7. For more information, see How to Enable the Exchange 2007 SP3 Password Reset Tool.
> Updated Search Functionality
Exchange 2007 SP3 includes updates to the Exchange Search (MSSearch) component. MSSearch provides support for creating full text indexes for Exchange stores. Exchange 2007 SP3 updates the MSSearch binary files to MSSearch 3.1.
> Schema Changes
Exchange 2007 SP3 includes Active Directory schema changes for certain Unified Messaging (UM) mailbox attributes. For more information, see Active Directory Schema Changes (SP3).
> Support for Right-to-Left Disclaimer Text
Exchange 2007 SP3 includes support for Right-to-Left text in e-mail message disclaimers in a right-to-left language, such as Arabic. In earlier versions of Exchange, when you use a transport rule to create a disclaimer in a right-to-left language on an Exchange 2007 Hub Transport server, the text appears incorrectly when you view it from Outlook 2007.
Exchange 2007 SP3 adds functionality to the transport rule setting to fully support right-to-left text in disclaimers.