If you are stuck on TFS 2008 and Office 2003, then after you install VS 2010, you will find the office integration to TFS is broken. This is by design as the VS team decided to only support Office 2007 and up with VS 2010.
If you are truly stuck in Office 2003 then here is what you can do, to get back the integration:
1. If you already dont have VS2008 and Team Explorer 2008, then install just Team Explorer 2008.
3. Install the VS 2008 Forward Compatibility update.
The office integration functionality is provided by a COM dll called “TFSOfficeAdd-in.dll”. To get back integration with Office 2003, you need to unregister the VS2010 version of this dll and then register the VS2008 version of this dll. (The dll is found in the “Common7\IDE\PrivateAssemblies” folder of the version specific Visual Studio installation folder).
Here are the commands:
Unregister VS2010 version of TFSOfficeAdd-in.dll
regsvr32 /u "c:\Program Files\Microsoft Visual Studio 10.0\Common7\IDE\PrivateAssemblies\TFSOfficeAdd-in.dll"
Register VS2008 version of TFSOfficeAdd-in.dll
regsvr32 "c:\Program Files\Microsoft Visual Studio 9.0\Common7\IDE\PrivateAssemblies\TFSOfficeAdd-in.dll"
When you are ready to upgrade to Office 2007, just reverse the above 2 commands (i.e., run regsvr32 /u on the VS2008 dll and regsvr32 on the VS2010 dll).