Sonic Rush

GameFAQs
Offers release data and a message board.
http://www.gamefaqs.com/portable/ds/data/920803.html

GameSpy
Includes a preview, news, and screenshots.
http://gba.gamespy.com/nintendo-ds/sonic-ds/

IGN
Preview, news, FAQs, screenshots, and videos.
http://ds.ign.com/objects/683/683045.html

Sega of America: Sonic Rush
Official site, with game information, screenshots, and movies.
http://www.sega.com/games/game_temp.php?game=sonicrush