Right click and "Unblock" the zip file after downloading.
The zip file contains two files:
Copy both these files to the Visual Studio AddIns folder.
By default this is %USERPROFILE%\Documents\Visual Studio 2010\AddIns
E.g. on Windows 7 C:\Users\Me\Documents\Visual Studio 2010\AddIns
For Visual Studio 11 it will be %USERPROFILE%\Documents\Visual Studio 11\AddIns
If the AddIns folder doesn't exist, just create it in the Visual Studio 2010 or Visual Studio 11 folder.
When you next start Visual Studio it should load SmartPaster.
If it doesn't, check in Tools/AddIn Manager... to see if it listed.
This version includes both C# and VB.Net support, and supports Visual Studio 11