There are many resources that address many common questions people have about Christianity...here are a few:

ONLINE:

www.billygraham.org/SpiritualHelp_Index.asp
www.greatcom.org/resources/toughquestions

BOOK:

Mere Christianity - C. S. Lewis
The Case for Christ - Lee Strobel
The Case for Faith - Lee Strobel
The Case for A Creator - Lee Strobel
New Evidence That Demands a Verdict - Josh McDowell
Who Made God? And Answers to Over 100 Other Tough Questions of Faith - Ravi Zacharias

Know of additional helps? Let us know!