I don't work with digital photos, etc., so I'm sure someone will jump in and correct me if this is wrong.
If you're simply talking about taking a photo and sharing it between/among parties, in order to be assured the color is being represented properly, you would have to make sure the digital camera is calibrated correctly to begin with and that all the concerned parties monitors are calibrated correctly too.
I don't know that much about the technical specs, etc., but, provided it was compatible with the equipment involved, couldn't you just make sure you were using the same ICC profile and make sure the monitor was calibrated for every party involved?
The Pantone Color Matching System is a set of special inks that allow you to be "sure" the printed material produced using those ink colors will be consistent no matter where you get your items printed.
Of course, there are so many variables that you can't really be 100%, absolutely sure: you have to pick your colors from a formula guide or chip set that is new enough and been taken care of properly to avoid faded colors, you assume that the printer will manufacture the custom inks to Pantone specs, you must make sure to see the ink color on the type of paper your material will be printed on (coated, non-coated, etc.) -- as you can see, there are a lot of variables that come into play. :) That being said, you're very safe in assuming the printed material will be a very good match if you specify PMS colors.
I'm not sure if there is anything of this sort for photographs or not; although I'm sure there probably is.
Pantone colors are also used in plastics, interiors, etc., so you might check their site to see if they have something that will help you in your project.
As korkus said, knowing what you're photographing might help too.