According to the latest issue of Famitsu, a very credible Japanese gaming periodical, Square Enix will announce a new chapter in the Star Ocean series at the Square Enix Party mid-May. The party is also purported to be showing off 10 Final Fantasy titles, including a "Final Fantasy that is not known by anyone," according to ad for the event.
As for which console the next Star Ocean will appear on is unknown. Developer tri-Ace, who is also known for Valkyrie Profile and Radiata Stories, has predominantly worked with Sony hardware. Their most recently-announced project, Infinite Undiscovery, is the anomalistic Xbox 360 title.
[Via Wii, PS3 Fanboy]