Alice and I definitely believe in the importance of catechizing our children. The unfortunate reality is that most Christians do not know the bible well and know even less doctrine. The typical American follower of Christ seems to know alarmingly little beyond the basics of the gospel message.
We want our children to know both what they believe and why they believe it. Because of this, we study systematically through the bible, usually reading a chapter or two per day (some weeks we do a better job of this than others). During our time of bible study, we also use a catechism.
As we catechize, we use the traditional question-and-answer format. We usually go question-by-question, answering together out loud. For example, the most famous question in the catechism we use is, "What is the chief end of man?" After I read the question aloud, we all answer together, saying, "Man's chief end is to glorify God and enjoy Him forever."
There are several different options for what catechism to use. This will obviously depend upon what your specific beliefs are. As Baptists, we have chosen to use a Baptist catechism. This catechism (pictured above) is published by Desiring God Ministries. The website description of this catechism says, "This booklet is a slightly revised version of 'The Baptist Catechism' first put forth by Baptists in 1689 in Great Britain. It is patterned after the well-known Westminster Catechism, and includes some comments in the early sections to help parents make things plain to their children."
To gain a sense for what this catechism is like, you can read it here.
You can order the catechism here.
I highly recommend using some sort of catechism with your children. It is amazing how much even little children can learn in a relatively short period of time. The beauty of the catechism is that kids both like it and benefit from it. They will learn truths that will remain with them for the rest of their lives. If learned at a young age, children may know a great deal of biblical doctrine even before they submit to Jesus Christ as Lord and Savior.