Let's say you already have Visual Studio 2005 Professional, but you now want to be able to connect to Team Foundation Server from within Visual Studio. Let's say you have a Team Suite CAL (needed to access TFS), but you want to connect to TFS using your existing VS Professional install, and avoid the "traditional" route of spending 3+ hours uninstalling VS Pro, SQL 2005, and everything else, then reinstalling VS Team Suite.

You could probably use the MSSCCI provider, but I sortof wanted to use the cool Team Explorer as a Visual Studio addin. So to do that, I believe you can

1. Download & install the Office 2003 Primary Interop Assemblies. Per this post, even though Team Explorer requires Office Project, the interops are all that's needed.
2. Download & install Team Explorer

Now you should be able to connect to TFS using Visual Studio Pro with the Team Explorer addin. This is untested (so far), but I'll be testing this theory extremely soon & letting you (my two faithful readers) know.

Mild rant: why is Team Explorer a 250mb download as an .IMG file? You'd think it could be way smaller if we only want the add-in version (instead of the standalone client), and in a ZIP file, too. Oh well.

Edit: I recently tested this process and it does indeed work. :)