To copy a work item template definition from one TFS project to another, install the TFS Power Tools and then type the following commands in the Visual Studio 2010 Command Prompt:
witadmin exportwitd /collection:http://tfsserver:8080 /p:"SourceProject" /n:"Work Item Type Name" /f:"C:PathToLocalFile.xml"
witadmin importwitd /collection:http://tfsserver:8080 /p:"DestinationProject" /f:"C:PathToLocalFile.xml"
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