I found the following article 10 Ways to Teach Your Children About Money to be very informative. I feel that the author Karen Weideman from ThriftyMommy.com has some very practical ideas on how to teach children about money.
Her article talks about teaching children that they need to learn how to save for the things that they want. She discusses how to talk to children about real daily expenses, so they understand that things cost money.
Her approach shows them that what they want is not the only thing that is important. This allows them to understand the concept of having to have money for what they need, such as the need for a roof over their head and food in their mouth.
I think her approach of speaking to children with the attitude that they are capable of thinking like an adult is very refreshing. If you treat children like they can think for themselves, they are more likely to learn to be able to think independently.