GameFAQs: Release data and a message board.
GameSpot: Offers news, previews, reviews, images, videos, and links.
GameSpy: Mario & Luigi: Partners in Time: Provides information, screenshots, and a movie.
IGN: Mario & Luigi: Partners in Time: Includes news, screenshots, videos, and a preview.
Wikipedia: Article, with a plot outline, character list, box art, and a screenshot.