My 12-year-old son has been questioning God's existence. Do you know of any resources that would be helpful to share with him? How about for adults as well?
I would recommend:
Children Demand a Verdict by Josh McDowell
Answers to Your Kid's Questions by Chuck Colson
Also, for adults:
Case for Faith by Lee Strobel
How Now Shall We Live? By Chuck Colson
Answers for Athiest, Agnostics & Other Thoughtful Skeptics by Calvin Beisner (this is out of print but can probably be purchased through http://www.addall.com/)