As a premium service, Chess.com provides a comprehensive library of instructional videos and a child-safe site, ChessKid, offering appropriate lessons, videos, and tactical quizzes.
Many sites, such as ChessCafe.com and ChessUSA, include chess videos and book reviews.
Plenty of online sites offer free instruction: Chessopolis offers extensive links to chess tutorials and lessons. Another information-rich site is About.com.