when you see a bird with colour-marks
you have to report the place, the date, the names of all birders that read the ring
  inscriptions: horizontal or vertical, way of inscription (top-bottom or vice versa)
  colour of marks
  position of marks: Nasal Saddle, Neck Collar, Wing tag, Leg Ring
  the birdspieces
then if possible: take pictures
  report the position of the metal ring

for sightingsin Italy only, please contact the INFS: recoveries@infs-epe.it,

another way see on cr-birding site where send your notes or contact the official EURING site