The official minisite for Yoshi's Island DS is up, and it is so very clickable! Make sure you slide your mouse pointer around, as there's music hidden in one of the flowers. Under "see more" by the DS, there's a very simple introduction to the game and the characters that's quite charming.
The bad news: the site content, while cute, is pretty thin for now, but they promise more is coming, so keep an eye out. The game hits stores November 13.