latitude and longitude designation and collection data

[Library]

          The California Academy of Sciences has recently acquired
          GIS software.  It is of great interest to us to use this
          software in conjunction with our existing collection's data.
          However, much of our existing data is without latitudinal
          and longitudinal designations.  Has anyone already
          undertaken the huge job of retrospectively assigning
          latitude and longitude to their collections data.  If so,
          what was done to maximize the speed and accuracy of the job?

          Karen Cebra
          Collections Manager
          Department of Ornithology and Mammalogy
          California Academy of Sciences
          kcebra at calacademy.org