Update: Promo video revealed
Thanks to Blade2t3 for the tip.
Original story (2/7/2008): The DS will be receiving yet more Tales treatment as detailed in a recent scan from Shonen Jump.
According to VGChartz, the game seems to be a blend of 2D characters and realistic 3D backgrounds and is thought to be in development by famed sub-developer Team Destiny.

The main character will be called Shing, whilst the heroine is Kohaku. It is thought that this, along with Chrono Trigger DS, will be part of the blow-out of four new DS RPGs that Famitsu will have coverage of next week. Not many details are available on Tales of Hearts yet, but it is known that the enemy designer is Keita Amemiya, the ship design is by Takuhito Kusanagi and the director will be Naoki Morita. A release is penned for Winter 2008 in Japan.
[ Thanks to C3 reader patjuan32 for the tip ]