I found myself in the role of the Business Analyst or BA for one of our important clients.  Finally, a chance to extract requirements.  After a kickoff meeting and a few work sessions, I had enough information to document the scenarios (use cases) and begin mocking up the interface.  Searching around for a nice Visio stencil,   I found a site that rang true and discovered the term "interaction designer".  Great read "Visio - the interaction designer's nail gun (3rd edition)" and the site has many good articles on the interaction designer. 

"The trouble is that the detail each audience requires differs vastly from the detail required by others, and the bulk of this detail is irrelevant to the needs of other audiences. The sensible approach is to limit the detail in the diagram to that which can be usefully applied by all audiences. The diagram thereby serves as a touchstone document for the development of more detailed documents specific to the needs of each audience." [Abbett.org]

Yes, the problem I faced with the Nail Gun mockup approach was how ridged the UI looked.  In reviews, many thought they were final screens.  A work colleague offered a stencil that was "fuzzy", a little hard to focus on, that he had used in the past.  Well, it fit the bill.  I mocked up the screens again using the "fuzzy" look/feel.  This round of reviews was like using a white board where project members offered up changes since it was just a few ideas written down.

 Download the Visio sketch shapes here: http://www.abbett.org/resources/SketchGUIShapes.zip.