I remember my Catechism classes vividly -- sitting through lectures, answering questions, and doing a lot of homework. These classes are handled by the Catechists (men and women who have been trained to give such teachings).
On the eve of 25th of September, 2013, the Vatican plans to release an app that would enhance access to the Catechism of the Catholic Church. For now, the only language available is Italian.
I am yet to see how different the app is from Laudate (an android app that teaches the Catholic faith), which is available in over 10 languages, has an offline Bible and some prayers and devotionals.