Of course, if your client/IDE supports the MSSCCI, then you can download the plugin (currently in beta). If you use another IDE (for example, Eclipse), then you might want to consider Teamprise. I was on holiday when Grace Francisco blogged about an MSDN webcast showing how you can:

Find out how you can use the Teamprise Plug-in for Eclipse to access the source control features of Microsoft Visual Studio 2005 Team System from within the Eclipse integrated development environment (IDE). In this webcast, we show you how to add new Eclipse projects to a Microsoft Visual Studio 2005 Team Foundation server, import existing projects from Team Foundation Server into Eclipse, and keep projects synchronized. We also look at the Teamprise Explorer client on a Linux virtual machine.

Presenter: Corey Steffen, General Manager, Teamprise