If you are looking for online flashcards, this site has a great collection (printing costs money).

Nice collection of games and stories. Games include variations of concentration/memory type games.

Pretty good list from a mutlilingual bookstore of radio stations that feature talk, music and other programming in Chinese. Very useful for listening practice.

Varying quality, but can be a useful aid and add some variety to learning.

Another online language learning program. Has a subscription fee to use, though there are ample demo materials available for evaluation.

A list put together by the Asia Society that tracks public and private schools in the U.S. with Chinese language programs.