The free Neocate iPhone app allows you to easily keep track of your childs nutrition and add information about symptoms that you observe. Upload photos directly from your phone and attach them to your diary entries to show your doctor exactly what happened. Use the reminder function to let your phone automatically remind you to update your diary. Transferring your diary to your doctor is especially easy with the built in export-via-email function.
The free Neocate Mobile Diary is available on the App Store.