Randy Newman has written an excellent book entitled Questioning Evangelism.
D. A. Carson writes: "This book reflects both a deep grasp of biblical theology and a penetrating compassion for people. How very much like the Master himself!" J. P. Moreland writes: "This book is must reading for those who want to learn how to bring apologetics into evangelism in a biblical and relationally sensitive sort of way."
If you want to read an excerpt, here's the article that started it all. [HT: New Attitude Blog]
Newman now has a sequel Corner Conversations, which I have not yet seen.