Square Note is a new smartphone Gregorian chant app. From its description:
Square Note puts a huge library of Gregorian Chant scores—over 600 unique chants and counting—right at your fingertips. Always wanted to learn how to read square note notation? Always wondered how to find all the amazing Gregorian Chants of the Catholic Church? Square Note brings the ancient music of the Church to your mobile devices, ready for you to utilize in your schola, your choir, or your home.Available for iPhone or Android for $2.99. HT: New Liturgical Movement.