Looking for the Add-In Manager in Microsoft Visual Studio 2010 Express? Trying to figure out how to install Add-ins? Sorry to say, but the ability to load add ins is not included in the express versions of Visual Studio. 🙁 It looks like you need at least the standard edition of VS.
It took me about 30 minutes of searching to learn this so I thought I would make a quick post in case it helps someone out.