Where are the Bootstrapper packages installed?

Question
How can I programatically determine where the Bootstrapper packages are located?   

Answer
If you would like to know how to programatically locate the Bootstrapper package location (if you were developing an installer for your custom package for example).  Check the following registry key:

HKLM\Software\Microsoft\.NetFramework\sdkInstallRootv2.0

Then append the string:

"Bootstrapper\Packages\"