There are two ways to install the PowerToys
* Source Code
Either way you need ReSharper installed.
If compiling from source, you need to reference the ReSharper assemblies which are located in %Program Files%\JetBrains\ReSharper\vX.Y
To install a plug-in from source code (this applies to any ReSharper plug-in and not only these PowerToys), you need to compile the source code and place the binaries under the %Program Files%\JetBrains\ReSharper\vX.Y\Plugins folder. If the Plugins folder does not exist, you need to create it. It is considered good practice to place each plug-in in a subfolder of it's own under the Plugins folder.
For example, to install ZenCoding plug-in, compile the ZenCoding.csproj and the resulting output should be placed under %Program Files%\JetBrains\ReSharper\v5.0\Plugins\ZenCoding.
Binary installs will be available soon from this site. Until then, you can grab the latest available binary installers from the ReSharper Early Access Program download page. The zip contains an MSI for each individual plug-in as well as a full installer for all of them.