Microsoft Exchange Server 2010 helps IT Professionals achieve new levels of reliability with greater flexibility, enhanced user experiences, and increased protection for business communications.

• Flexible and reliable – Exchange Server 2010 gives you the flexibility to tailor your deployment based on your company’s unique needs and a simplified way to keep e-mail continuously available for your users.
• Anywhere access – Exchange Server 2010 helps your users get more done by giving them the freedom to securely access all their communications – e-mail, voice mail, instant messaging, and more – from virtually any platform, Web browser, or device.
• Protection and compliance – Exchange Server 2010 delivers integrated information loss prevention, and compliance tools aimed at helping you simplify the process of protecting your company’s communications and meeting regulatory requirements.

System Requirements

• Supported Operating Systems: Windows 7; Windows Server 2008; Windows Server 2008 R2; Windows Vista
• Operating System for Installing Management Tools: The 64-bit editions of Windows Vista® SP2 or later, or Windows Server® 2008 SP2.
• PC: x64 architecture-based computer with Intel processor that supports Intel 64 architecture (formerly known as Intel EM64T) or AMD processor that supports the AMD64 platform.

Additional requirements to run Exchange Server 2010

• Memory: Minimum of 4 gigabytes (GB) of RAM per server plus 5 megabytes (MB) of RAM recommended for each mailbox
• Disk space
  • At least 1.2 GB on the drive used for installation
  • An additional 500 MB of available disk space for each Unified Messaging (UM) language pack that you plan to install
  • 200 MB of available disk space on the system drive
• Drive: DVD-ROM drive, local or network accessible
   

DOWNLOAD it from here: http://www.microsoft.com/downloads/details.aspx?displaylang=en&FamilyID=05741f65-2a7b-4070-879f-d74208d6171d#tm