I belong to ASMP; the American Society of Media Photographers. This professional organization's goal is to aid the profession of photography; to aid not only photographers, but also users/buyers of photography.
In that light, ASMP and AIA, the American Institute of Architects, has put together some guidance material on architectural photography. This covers things like selecting an architectural photographer, how a photography estimate works, licensing/usage of photographs, controlling costs, and even a checklist to make it work as smoothly as possible. This info can be found at http://asmp.org/commissioning/overview.html. This has much more detail and great info than I can address here. I strongly suggest that you take a read; it will help you and all those needing images to ease their involvement with photographers. We can concentrate on the details of your photographic need instead of the process. I look forward to working together.
Greg
