Final Fantasy XIII demo this year? You might have to try your luck with a Japanese copy as Square Enix has said that "at present the FINAL FANTASY XIII demo will only be available in Japan with the Blu Ray release of Advent Children Complete, but we hope to have further news in the coming months." Feel free to keep your fingers crossed for that.
With FFXIII releasing on both PS3 and Xbox 360 outside of Japan we imagine demo distribution will be a bit more complex. Especially since development on the 360 version hasn't even started, so a demo will be a long way off. We have a feeling us English speakers are going to be sitting here twiddling our thumbs for quite a while as our Japanese cousins are having a whale of a time.