Building the SDK in 64bit

I’m using win7(64), and new to CUDA and VisStudio2010Prof.
I am able to build the 4.1 SDK samples in 32bit. (I just click “build”.)
I’d like to build a 64bit executable.

How can I tell VS to build the 64bit version?
Do I do something with the .SLN file?
Do I touch the Cuda code?

Thanks

Inside VS2010,…
BUILD tab,…
CONFIGURATION MANAGER,…
ACTIVE SOLUTION PLATFORM,… select “x64” rather than “Win32”

F7 will now build the 64bit executable.