According to 1UP, the May issue of EGM contains a rumor that Final Fantasy XIII will be showing up at next month's E3 for "a brief teaser video and confirmation from [Square Enix] that the RPG will be a PS3 exclusive." RPG fans, rejoice!
What's a little shocking is that FFXIII would be unveiled before FFXII is even released outside Japan, but "rumblings" have apparently also been picked up that "Final Fantasy XIII is practically close to being finished" already. With all the delays to XII, it's certainly more than possible that a second team working on XIII's already got something to show by now.
"Rumor: Final Fantasy XIII PS3 exclusive at E3" - 05.04.06