Chinese languages

You can also study for the hsk test online at http://www.visualmandarin.com
You will find many useful exercises there.

Visualmandarin is a great language tool to learn chinese online . It is much easier to learn a language by associating visual concepts with words, rather than just simply focusing on memorizing words outside a context. Visualmandarin offers many exercises that help the student on tone recognition an...

Learning how to write chinese characters is the easiest way in which you can memorize chinese characters. Try visualmandarin's Chinese stroke order dictionary where you will see the basic chinese strokes for many chinese characters.

I would say that http://www.visualmandarin.com is also a possible contender. They even have exercises to test your pronunciation, lots of exercises to learn pinyin and so on.

You can find people at http://www.visualmandarin.com who will be willing to teach you mandarin as long as you also teach them english.
You might also want to subscribe to the site above, it has many useful lessons/videos/exercises for you to learn chinese