Catechisms of the Catholic Church

There are basically only two catechisms of the Catholic Church. The older one is called the Baltimore, with editions 1 thru 4 that are age-specific.

Baltimore Catechism No. 1, available at Project Gutenberg.. An abridged edition for younger students.
Baltimore Catechism No. 2, available at Project Gutenberg.. The main edition.
Baltimore Catechism No. 3, available at Project Gutenberg.. An expanded edition for older students.
Baltimore Catechism No. 4, available at Project Gutenberg.. An annotated edition for teachers.
Baltimore Catechism Summary

The latest catechism is the one approved by Pope John Paul II, and has a great deal more teachings. You'll find many references to the teachings of Vatican Council II which expands our knowledge of current doctrine. It is often shortened in references as the CCC (Catechism of the Catholic Church). There is an abbreviated version of this called the Compendium of the Catechism, but it covers the basics of these latest teachings.   Searchable CCC

Another handy link: This site has a handy search string, so if you type in a word at the bottom of the page, all references to that topic will be shown. http://www.scborromeo.org/ccc.htm

Sources:  Christian Forum and  http://www.scborromeo.org/ccc.htm