LearnEarly by Megatronic Games
LearnEarly is a developmental learning aid for toddlers and pre-schoolers. It was designed to help young children learn about and recognise simple numbers, letters, sounds, musical instruments, colors, and shapes.
The app is brightly colored and simply and intuitively laid out making it easy for toddlers to use.
LearnEarly usually costs $1.99 but it free for a limited time.
Developer Website: http://www.megatronicgames.com