I was poking around in the Apple App Store today, and found Pocket LD, which: “is a photometric database and calculation tool for theatrical and TV/Film lighting professionals.  Simply enter your throw distance, than select manufacturer, fixture and a lamp to calculate beam/field diameter and fc/lux.”  Checking out the website for the source, I came upon LightingiPhoneApps.  Pretty groovy…they have the LD app as well as a bunch of other apps relevant to LDs, stagehands and other assorted techs.