I just finished reading a book by now retired Anglican Bishop John Shelby Spong entitled
"Rescuing the Bible from Fundamentalism: A Bishop Rethinks the Meaning of Scripture" that my atheist (although he would rather call himself a secular humanist) neighbour loaned me. I was very interested in this book because I felt that it would help me to get into my neighbour's mind so that I could communicate the gospel with him more effectively. If you have ever read any of Spong's work you will probably have reacted strongly to many of his assertions. I marked many of his statements that stood out to me as I read the book intending to go through them and comment on them, even if only for my sake.
Always allow challenges to your faith to drive you deeper into the word of God. You will never be disappointed if you seek God for His wisdom, and He promises to give it to us without finding fault to all those who ask with faith (James 1:5-6).
Jonathan Sarfati, whom I have come to respect, published this excellent response to Spong's work
here. If you want to see a very solid yet winsome defense of the "Fundamental" Christian Faith both through scriptural support and through other secular sources (refuting several of Spong's claims), I highly recommend reading this article.