As a pastor, you just don't have much time to read. I understand that quite well. So, it's not surprising that the most common question I get asked is, "If I have time to read just one book on biblical counseling, what should it be?"
Here is my choice: Paul Tripp's Instruments in the Redeemer's Hands.
Using Christ's example, Tripp describes four basic steps (Love-Know-Speak-Do) that show believers how to use God's word to help others. The book covers lots of helpful topics such as: identifying with the sufferer; clarifying responsibility; asking 'heart-piercing' questions; etc.