While Namco Bandai announced Tales of Vesperia for the Xbox 360 in North America there wasn’t a firm decision about which console(s) the game would come out on in Japan. Unsurprisingly, Tales of Vesperia will be an Xbox 360 in the land of the rising sun too, which makes this the first Tales game only found on a Microsoft console.
That is unless Vesperia pulls an Eternal Sonata and comes out on the PlayStation 3 with extra content a year later. I suppose it could happen since a handful of games like Lost Planet and Enchanted Arms start out with “only on Xbox 360” on their label only to become PlayStation 3 titles in the future.
Update: Microsoft's press release mentions Tales of Vesperia will include Xbox Live support. Whether this means online co-op or pay-to-play downloadable side quests is anyones guess. Also a trailer for Tales of Vesperia is scheduled to come out sometime this month on the Japanese Xbox Live Marketplace.