I came across this website, iloveatheists.com, listening to an Unbelievable podast. The creator of the website found out in debates with atheists that the same arguments kept coming up. So with a desire to collect answers, he made this website to be his personal answer key.
The website features a "Top 100" list of challenges that are often posed by atheists, with answers given by iloveatheists' creator, Todd Pitner.
Check it out. And love an atheist.