http://www.microsoft.com/downloads/details.aspx?FamilyId=15DB9989-1621-444D-9B18-D1A04A21B519&displaylang=en
Date Published: 3/6/2008

Setup Step:
1) uninstall any previous versions of the ADO.NET Entity Framework
2) Download and install Microsoft .NET Framework 3.5 and reboot the machine if prompted. Be sure to follow the instructions on the download page and in the .NET Framework 3.5 Readme. Note: Microsoft .NET Framework 3.5 is included in the Visual Studio 2008 installation and you do not need to reinstall the Framework if you have already installed Visual Studio 2008.
3) Download the Entity Framework Tools December 2007 CTP and setup
3) Download the correct version of the ADO.NET Entity Framework for your architecture from the links below: EFB3SetupX86.exe for 32-bit versions of Windows and EFB3SetupX64.exe for 64-bit versions of Windows.
4) Run the installer and follow the instructions in the setup wizard.

See the ADO.NET Entity Framework Readme for a list of known issues and workarounds.