Rob Caron has a great post showing the macro he created in Word that he uses as his email editor (the default in Outlook) so he can quickly turned references to Work Item numbers into links to the details.

His macro:

Sub MakeWorkItemLink()
   ActiveDocument.Hyperlinks.Add _
     Anchor:=Selection.Range, _
     Address:="http://server:port/WorkItemTracking/Workitem.aspx?artifactMoniker=" & _
       Selection.Text, _
     SubAddress:="", _
     ScreenTip:="Click to view this work item", _
     TextToDisplay:=Selection.Text
End Sub