[all books will be linked to their amazon.com pages]
I was asked about this today. The book that readily came to mind was Did Adam and Eve Have Belly Buttons?: And 199 Other Questions from Catholic Teenagers by Matthew Pinto (an acquaintance of mine). Also, he has another related book: Did Jesus Have a Last Name? And 199 Other Questions from Catholic Teenagers.
The other Catholic writer for teenagers I know about (and also know a bit personally) is Amy Welborn, a terrific writer (her blog, Open Book, gets over 6000 hits a day - by comparison mine gets about 600! I have no idea how she accomplishes this marvel of web traffic, but I'd love to obtain the "secret"). She has written several books in a series called Prove It! . . . (designed for readers about 12 and older). Here they are:
Prove It! God
Prove It! Jesus
Prove It!: Church
Prove It! Prayer
Prove It! the Catholic Teen Bible - NAB
Also, from my own writing, The New Catholic Answer Bible (NAB) would be good, I think, for teenagers. It offers 88 one-page inserts which give a capsule summary of arguments regarding all the major apologetic / theological topics, with biblical support and references to the Catechism of the Catholic Church. Half were written by Paul Thigpen and half by myself (the original Catholic Answer Bible included only my inserts).
Although I don't try to write specifically for teenagers (I make little attempt to simplify anything, for better or ill), and my writing is probably most suitable for those with some college and/or a bit of prior theological education (by that I mean Sunday School, catechism, Bible study groups, good Catholic teaching at home, several books on theology read, etc.) - some folks regard it even as "semi-academic" -, it seems like a lot of those in their late teens and early 20s visit my website and blog.
Other books I found for teenagers and/or "young people" while looking at the above pages and surfing around amazon's various "lists" and so forth, are:
Father McBride's Teen Catechism: Based on the Catechism of the Catholic Church (Alfred McBride)
Teen Guide to the Bible (Alfred McBride)
Ask the Bible Geek: Answers to Questions from Catholic Teens (Mark Hart)
If You Really Loved Me: 100 Questions on Dating, Relationships and Sexual Purity (Jason Evert)
Real Love: Answers to Your Questions on Dating, Marriage and the Real Meaning of Sex (Mary Beth Bonacci)
We're On a Mission from God: The Generation X Guide to John Paul II, The Catholic Church and the Real Meaning of Life (Mary Beth Bonacci)
The International Student Bible For Catholics Where Straight Answers Are Standard Procedure
Letters to a Young Catholic (Art of Mentoring) (George Weigel)
The Catholic Youth Bible: New Revised Standard Version : Catholic Edition (Brian Singer-Towns)
For younger children, more books are listed in Rich Leonardi's guide, So you'd like to... Hand on the Catholic Faith to Your Children