This post should be under the category "you learn something new every day". First, some background. In my earlier years here at MS as a developer, one of the things I wrote was the VS Toolbox support for managed components. You know that gnarly "Choose Items..." dialog? Yeah, I did the ".NET Components" tab of that thing, all the code that surfs the assembly looking for components, as well as the code the manages the items that are on the toolbox and does the funky auto-populate stuff when you build projects.
So I was surprised to learn that there's a very easy way to add your Toolkit items to the toolbox. I'm still fairly mistified that it works. But I digress.
1) Create a tab on your toolbox by right-click then "Add Tab", and name it something creative like, say, "Atlas Control Tooklit"
2) Open the location where you installed the toolkit, and navigate to the "SampleWebsite\Bin" directory.
3) Drag "AtlasControlToolkit.dll" onto the new tab you created.
Like magic, all the Toolkit components will be added to the toolbox!