Chinesesphere helps students of all ages to learn Chinese online with Online Chinese lessons from experienced teachers. Also offers Kids Chinese Lessons, K-12 Chinese Lessons.
This is a superb site for finding downloadable podcast for kids to learn Mandarin. Not all the resources are free, but there are lots of really useful resource that are, including over a hundred audio files lessons and for learning pinyin.
http://ictmagic.wikispaces.com/Mandarin+%26+Chinese+culture
Chinese New Year Collection with many different lessons at all age levels along with downloadables to use. If you are expecting your students to have global literacy, you cannot afford to ignore China. This is a fun time to teach about it - kids love dragons and fireworks!