Larry Birkhead is the father. He just announced to the world, "I told you so." [T]he DNA results were unveiled inside and it would seem it's a DNA match for Birkhead and Dannielynn.
The DNA test, just revealed live on TV, has confirmed that Larry Birkhead has been proved 99.9999% that he is the father of Anna Nicole Smith's daughter Dannielynn Hope Smith. See, I told you so, too. [Source]