"A informer inside Square Enix has told GOONL!NE that Kingdom Hearts III is in pre-development and will be unveiled very soon."
this is just a rumor,,so don't take it seriously,,,but the article sugests that it might be unveiled in the SE event(which is in the next 6-9 hours)
http://gamzsonev3.wordpress.com/2008/08/02/rumor-kingdom-hearts-iii-to-be-unveiled-soon/