Shockingly, a new Lego game by Warner Bros and Traveler's Tales was announced exclusively for the DS- Lego Battles. The press report can convey it's theme better than I can so enjoy:

London – Feb 4. 2009 - Warner Bros. Interactive Entertainment and TT Games are teaming up with The LEGO Group to deliver LEGO® Battles for Nintendo DS™, a videogame based on classic play scenarios in evergreen themes that include LEGO Castle, LEGO Pirates and LEGO Space. Produced by TT Games, developed by Hellbent Games and published by Warner Bros. Interactive Entertainment, LEGO® Battles pulls three LEGO themes together to create a unique extension of the LEGO build-and-play experience that stays true to the customization and humor that are the foundation of LEGO videogames. The game is scheduled to be available in the United Kingdom this summer.

LEGO® Battles offers a new kind of “build and battle” LEGO gameplay. Through six distinct story lines, players build their own LEGO bases and battle teams as they engage in over 70 different levels, mixing and matching units to create the ultimate customized LEGO squad. These unique LEGO battles teams see pirate swordsmen fighting side-by-side with wizards and aliens; dragons battling ninjas; and pirate ships launching broadsides against spacecraft and knights! Players can also challenge friends on the battlefield in multiplayer mode through wireless DS multi-card play.

“LEGO® Battles offers players the action-packed and humor-filled gameplay that make LEGO games great, along with the added bonus of linked multiplayer battles on DS,” said Tom Stone, Managing Director, TT Games Publishing. “We are excited to introduce a new LEGO videogame experience to fans and young gamers and look forward to expanding upon the beloved toy lines.”

http://gonintendo.com/?p=71537#more-71537

This was actually a rumor that originally started on a Gamefly listing. It's now official. I originally posted the rumor here:

http://gbatemp.net/index.php?showtopic=132360

There are no screens or videos as of now. And no word what the game will even look like. Sounds like some sort of RTS. If so, I'm imagining the game will employ either 2D or a hybrid of 2D and 3D. The DS, and especially the previous Lego DS games have had trouble showing more than about 6 characters on screen at once without slowdown.