According to Aniplex's website, there will be some sort of Persona concert on the 22nd of August. Check it:
Judging from the pictures, it seems like there will be music from Persona 3, Persona 3 FES, Persona 4, and the anime Persona - Trinity Soul. It seems like Shoji Meguro and Lotus Juice (the rapper from Persona 3) will be present, among others. I don't know Japanese, so any translation of the details would be welcome.
I would certainly attend if I were in Japan. But it sure sucks that they seem to totally disregard the first two (er, three) games in the series, which have far better soundtracks than P3 and P4.