Send audio output of MacBook to iPhone for remote listening

Is it possible to send audio from music in iTunes, or from movies on Netflix, or video game sounds, etc., from my MacBook and receive and listen to the audio on my iPhone? I'm thinking of this working like wireless headphones, except with a really long cord. If there is a way could you let me know how the solution works, I'm interested in creating my own script/app to do this if it's not too daunting. If its important, I'm running an old 2009 MacBook, running Snow Leopard.