With the second and final part now available for BioShock Infinite's Burial at Sea DLC, Irrational Games has posted three full, original songs from said DLC to its official website, along with some commentary from the game’s Music Director, Jim Bonney.
Bonney describes the first song, “Little Sisters’ Song,” as an idealistic musical conversation between “Mama Tenenbaum” and the little sisters. “I was thinking about ways to create depth in daily life in Rapture, and thought that the Little Sisters’ Home could use a little propaganda music,” he said. “A song that would ease the minds of the citizens that little girls being taken from their families was really just another example of living the Objectivist’s Dream!”
You can find a more in-depth commentary on the other two free songs, "The Pie Song" and "Old Man Winter Jingle," through Irrational's official blog
plus each of the songs to download.