Booktrack is amazing and free! It allows you to take a piece of writing and add sound. When a person reads your writing, they will be also listening to music or sound effects that you have added. Watch this video explanation:
There are also hundreds of stories just waiting to be read with music.
Choose to import your own writing or use one of the free books available. Book track is very easy to use. There are free video tutorials to watch and learn how. I highly recommend giving Booktrack a try!