Sight Reading Trainer (iOS) app for $0.99
This application helps you learn how to read sheet music in a very short amount of time. Simply play it for five minutes a day and in less than a week you'll be able to recognize any note in the treble clef that you see.
The game starts at level one with three notes only. If you score more than 20 correct answers you'll move up to the next level and will be challenged with additional tones.
If you score less than 10 correct notes you'll be moved one level lower, so that you can concentrate on a simpler set of notes and therefore improve your accuracy.