The artist and title of Tales of Symphonia: The Animation United World Episode's theme song were revealed at Tales of Festival 2011.
According to reports from various fans attending the Festival, the song will be titled ????????? (HO?N?TO?U?SO, roughly T-R-U-E-L-I-E) by Me. The one from Radiant Mythology 3's opening theme, not myself.
Other than that, the first volume of this final arc is dated for a fall release this year.