I've made reference to and quoted from the Catechism of the Catholic Church several times on this blog. It is a wonderful and wonderfully useful book that contains pretty much all the essential teachings and beliefs of the Catholic Church in a concise and easy-to-navigate format. If you've got a question about what the Church believes about a given subject, chances are you can find the answer in the Catechism. Pope John Paul II called it "a sure norm for teaching the faith."
Here's an episode of That Catholic Show, a video podcast by Greg and Jennifer Willits, who run an apostolate called Rosary Army. It's a little silly, but it's fun, and it gives a good introduction to the Catechism.