Repetition is of the utmost importance at this age in learning everything - the alphabet, numbers, colors, and even the names of notes. We have proof of just how much these little brains can soak up at such early ages. For instance, with the Suzuki technique, the child begins playing immediately. Eventually every student must take the plunge and learn to read music. Flash cards were basically the main teaching aid for naming notes.
Children love to play cards, especially ones with such humorous pictures and brilliant colors.
You can always simplify the games for young children. With only these 5 notes, you can play 'Go Fish'. They will begin matching the notes and proceed to figure them out on their own very quickly. Memory' also works well with young ones. Use the same five notes in two different suits and place the ten cards face down on the table.