The King’s Singers Masterpiece, the last 400 years of choral music in 9 minutes.
Solfeggio for the 21st Century is an up-to-date system which corrects some of the illogical flaws of traditional solfege and provides answers to chromatic problems posed in 19th through 21st-century repertoire. Any system (traditional solfege, numbers) helps the singer think through and hear complicated notation and combined with internal identification skills, helps singers become stronger musicians.
A New Approach to Sight Singing by Berkowitz, Frontier and Kraft– published by Norton
A New Approach to Sight Singing: I recommend the old Fourth Edition because this edition is excellent, cheap and widely available online as a used copy for less than $10 (including shipping). This book has hundreds of graded exercises which will help you build your SS skills. Use in conjunction with Solfege for the 21st Century (above) and use moveable do.
Modus Novus by Lars Edlund–published by AB Nordiska Musicförlaget
Comments by Paul Wiens, who taught Sight Singing at the Wheaton Conservatory of music for a decade: This book is quite expensive compared to A New Approach; online prices range from $50 and above; the problem is that it is far-and-away the best pedagogical tool available. The exercises in Modus Novus have proven effective in teaching the reading and hearing of intervals in non-harmonic contexts. Edlund’s first chapter focuses on major and minor seconds and then each chapter adds another interval; the result is that each chapter is more difficult than the preceding. With university students and beyond, Wiens recommends using this text simultaneously with tonal studies (rather than waiting as the author suggests). Use in conjunction with Solfege for the 21st Century (above) and use fixed do.
Forward from the Text by Lars Edlund: This textbook is an attempt to tackle the problems connected with reading of 20th-century (and 21st-century) music that is not major/minor-tonal. It has been evolved out of the author’s practical experience as a teacher in aural training the the Royal Academy of Music in Stockholm. It is desirable that the student should be proficient in reading major/minor tonal music before starting with Modus Novus.
An interactive learning resource which will help you learn basic music theory.
Handy chart which helps to identify keys and learn sharps and flats.
Musical Notation showing chord sequence with diction syllables.