To connect to a Team Foundation Server (TFS) with Visual Studio 2008, you will need to download and install the “Visual Studio Team System 2008 Team Explorer” plugin.
Microsoft Visual Studio Team System 2008 Team Explorer is a simplified Visual Studio Team System 2008 environment used solely to access Team Foundation Server services.
Once the Team Explorer is installed, open Visual Studio 2008 and go to Tools > Options > Source Control > Plug-in Selection. In the Current source control plug-in: drop-down box, select Visual Studio Team Foundation Server.
For convenient access to your TFS, you can dock the Team Explorer window to wherever you prefer. To do so, in Visual Studio, go to View > Team Explorer. Once the Team Explorer window appears, move and dock the window to your preference.