A modification of a library with the same name by Adafruit Industries that allows playing sound from an SD card directly on your Arduino board without any Digital to Analog Converter (DAC). It uses pin 3 on your Arduino Uno board to push out the sound. Just plug a soundjack from an amplifier and share ground with the Arduino to listen to the sound.
The idea behind this library is having a minimal setup to play sound from an SD card attached to the SPI pins on an Arduino board. Please note that there are limitations on the kind of WAV files you can use. For a better explanation on how to create the right type of sound files, visit: http://cuartielles.com/verkstad/edu/Courses1BitSound/PlayWAVsound
(c) 2013 Arduino Verkstad, D. Cuartielles, X. Yang, C. Leivas
Of course this code is licensed under GPLV3, just read the license file and chill out