Chrono Trigger DS will be hitting store shelves in Japan on November 20th, with a North American release following soon after on November 25th. A European release date has not yet been specified, though it has been speculated to be released sometime in early 2009. Also remember that you can always import the US version if you're that impatient.
Apparently, this DS remake will also have a different ending,
While it may not have received a visual upgrade, Chrono Trigger was one of the best RPGs on the Super Nintendo (this version now retails for $50+ on ebay), and I recommend you buy it regardless of it's graphics (which, for a 2D RPG are not at all bad).