TeamCompanion v4.3 supports Team Foundation Service Preview (tfspreview) and is able to display data from tfspreview projects.

In order to connect to the Team Foundation Service Preview you need to install Service Pack 1 for Visual Studio 2010 together with the KB2581206 hotfix.
Regarding this here comes one very important note - if you installed KB2581206 hotfix before September 1, you’ll have to manually uninstall, download and reapply it again, because it was changed in the meantime although the hotfix name remained unchanged. With the old hotfix, you’ll be able to connect to the tfspreview using Team Explorer, but all other clients including TeamCompanion will fail to connect.

Once you installed all required prerequisites you can connect to the tfspreview server the same way you would connect to any other server. First, you need to add server to the list of known Team Foundation Server servers:

The most important detail here is to define that connection uses HTTPS protocol. After you click the OK button, you’ll get the sign-in dialog. In order to sign-in to the tfspreview server your Windows Live ID account must have some previously assigned permissions.

Once you establish a connection tfspreview projects will be treated same way as any other non-cloud Team Foundation Server project and you’ll find it in the Outlook’s navigation pane.

And voilà, you’re connected to the tfspreview server, could that be any easier!?