More learning Mandarin web sites...
If you go to the bottom of the page, there is a chart where you can select different pinyin and hear how it is pronounced. There are also some matching games that the kids might find fun. http://www.newconceptmandarin.com/support/Intro_Pinyin.asp
Numbers: http://hua.umf.maine.edu/Chinese/games/numbers/chinese/one.html
Colors: http://hua.umf.maine.edu/Chinese/stories/xinxin/saving/colorc.html