Using [CommonAppDataFolder]\Microsoft\MSEnvShared\AddIns does the job on any windows version.

Source : http://www.mztools.com/articles/2008/MZ2008001.aspx

GoToFile Add In - Navigate Large Visual Studio Solutions Quickly. Free source code and programming help

How To Show Full File Path (or Anything Else) in VS Title Bar

Raise an instance of the Visual Studio IDE to the foreground.

How to: Fix 'Application is Busy' and 'Call was Rejected By Callee' Errors

Occurs when you get an RPC_E_CALL_REJECTED (System.Runtime.InteropServices.COMException).

How to: Get References to the DTE and DTE2 Objects

Walkthrough: Debugging an Add-in Project

HOWTO: Automating Visual Studio .NET from outside the IDE

Explains how to keep IDE alive or not even when automation is done.

Generate Load Keys

Also refered has PLK, package load key, vsip key generator.

Easy tutorial on how to install the package load key (PLK).

http://msdn.microsoft.com/en-us/library/bb165968%28VS.80%29.aspx

Tutorial: Simple VSPackage Deployment

Install and Deploy  a package.

How to: Implement a Library That Supports the Call Browser Tool

In order to add new items to existing Visual Studio menus the GUID of that parent menu must be determined. Therefore, to retrieve the GUID of any menu, toolbar or command, Dr. eX and Pablo Galiano proposed to use a registry setting then by using CTRL+SHIFT on an element the GUID would appear. It works but only in Visual Studio 2005. In order to work in Visual Studio 2008 it needs to be changed from 8.0 to 9.0.

Windows Registry Editor Version 5.00
[HKEY_CURRENT_USER\Software\Microsoft\VisualStudio\9.0\General]
"EnableVSIPLogging"=dword:00000001