I got a few mails and saw a few forum posts about the confusion created by new locations for dll/exe in beta2. So here is where you can find LINQ to SQL related files.

• New .NET Framework 3.5 DLLs (green bits) are in: Program Files\Reference Assemblies\Microsoft\Framework\v3.5\
• SqlMetal.exe is in Program Files\Microsoft SDKs\Windows\V6.0A\Bin\

Another source of confusion - designer vs. SqlMetal

• The visual designer for generating mapped LINQ to SQL classes is a part of Visual Studio 2008. You need to install some SKU of Visual Studio to use it.
• SqlMetal.exe is a command line tool that is a part of the Windows SDK and lives in the same directory as similar command-line tools like Xsd.exe