While it appears it's still in the early stages of production, the Persona 3 movie—which was originally teased after the credits of the Persona 4 movie—now has an official website, as well as a Japanese Twitter account.
The site currently just displays a teaser image and a clock showing the time in Japan.

Heads up, we'll probably want to keep an eye on that Twitter account for more info!
©Index Corporation/劇場版「ペルソナ3」製作委員会
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Joseph Luster is the Games and Web editor at Otaku USA Magazine. His blog can be found at subhumanzoids. Follow him on Twitter at @Moldilox.