Abraham Piper: "The full text of Don't Waste Your Life is now available online for free in a format optimized for the iPhone."
A little testimony about this: the folks at DG gave me a heads up about this site last week. I was scheduled to give a talk on vocation at CrossWay Community Church in Kenosha. So while waiting in the car while my wife ran into the store, I was able to reread a good chunk of Piper's chapter, "Making Much of Christ from 8 to 5"--which I would highly recommend! The entire chapter read very well on my iPhone.