If you want the antiquated Revit 2011 templates, go here.
If you haven't heard, the API for Revit 2012 has been updated to support .NET 4.0. Your .NET 3.5 and Revit 2011 Add-ins will still function with Revit 2012 (with some key edits to your .addin manifest files) but you will no longer be able to debug .NET 3.5 Add-Ins with Revit 2012.
I like to maintain separate templates for each flavor of Revit that I develop for since the paths to the API references are different for each product.
All you have to do is export a project as a template (the result will be a zip file) and place them under your current user's profile at:
"%USERPROFILE%\Documents\Visual Studio 2010\Templates\ProjectTemplates\Visual Basic".
It is important to place your templates into a sub directory (we'll name ours "Revit 2012") and to NOT unzip the template files. Leave the zip files intact and this will work just fine. Your directory structure should look something like the image below.
For you lazy folks... here are the links to the preconfigured templates: