If you are trying to add a PMS color into a color photo, you are in real deep.  If you are trying to 
lay a flat PMS color over a flat photo, you can do that as a rectangle set to overprint in Illustrator.

I will need to know more before i can advise you the best way to do whatever it is you are trying to do.

Britt

Linda Feltner wrote:
> Thanks, Britt:
> They told me either CMYK or RGB, so I didn't convert it to CMYK, but 
> will do so now.
> I sometimes have trouble colorizing to a specific PMS color in PShop, it 
> looks different than specifying it in Illustrator.
> I do it both ways, but somehow was under the impression that it could be 
> done with an RGB file as well. I'll try it in CMYK.
> Many thanks,
> Linda