1UP

Preview, by David Smith: "modes include a story-driven campaign, a nonstop survival mode with more missions to clear, a trial mode for learning basic strategy, and a mysterious 'combat' mode that apparently uses the touch-screen interface in some fashion.
http://www.1up.com/do/previewPage?cId=3135268&did=1

GameSpot

Preview, by Justin Calvert: "Advance Wars DS will boast all-new missions and a number of new CO characters, and the new battle system will see players using the bottom touch screen to issue orders to their ground forces while commanding their air forces o
http://www.gamespot.com/ds/strategy/advancewarsds/preview_6109910.html

Nintendo Insanity

Preview, by Marcel: "...Advance Wars DS is turning out to be a game in which enthusiasts of the series and casual gamers alike are sure to pick up..."
http://www.n-insanity.com/modules.php?module=previews&id=68

GameFAQs

Contains information and a message board.
http://www.gamefaqs.com/portable/ds/data/924889.html

GameSpy DS

Includes information, news, and screenshots.
http://gba.gamespy.com/nintendo-ds/advance-wars-ds/