The thing that worries most non-specialists teaching language is pronouncing words correctly from a book. This is where Forvo is is priceless. Native speaker users and the site itself have uploaded audio clips of word for us non native speakers to copy. The site has 250+ languages uploaded. I tested the Mandarin section, as I understand that, and it was faultless. An amazing resource.
http://ictmagic.wikispaces.com/Languages%2C+Culture+%26+International+Projects
Lexipedia has a great looking interface which will make you children want to look up words. Type or click on a word to make a word web and see definitions.
http://ictmagic.wikispaces.com/English