Supposedly there was a teaser ad in a japanese magazine this month, followed by a teaser site by Square that just launched:
http://www.square-enix.co.jp/ctds/
Looking at the evidence (or just the url), it seems like a safe bet that Chrono Trigger is heading to the DS in some way, shape, or form. I'd rather a sequel instead of another cash-in remake, but I'd love if they could somehow create all of the time periods in 3D.