Nearly as important as your own saving habits is teaching your kids to save money. You should start as soon as possible, from their first allowance is ideal.
A simple way to start is with a piggy bank. You should move things up to a savings account at the bank eventually, but younger kids will love seeing the real money right there. Encourage them to occasionally count out the money and see what they've saved.
A goal is a great thing for a child to have for their savings. One of my children is saving up for a harp. She dreams of learning to play one, and knows what a lower range one for learning to really play costs.
Early on, you should insist on a certain percentage of allowance or other money earned or given being saved. Let them have a little fun - it's their money, after all, but guide them in making good purchasing decisions.
It's okay for your kids to make occasional mistakes in how they spend their money. It can be a really good lesson. They're going to have conflicting wants at times, and you can use this to help them learn that no one gets everything they want in life, but saving up for the things they want most can be worthwhile.