I was op. upgraded once on airtran to biz class, but I was dressed nice than post pax. not sure if that counts, but yeah it was the agent at the gate who did it for me.

book on tipping is Tipping for Success.

Its more about how to be effective when tipping, not how to bribe people. Its a concise book, and while much of the advice is common sense it is still worthwhile. I have to admit, I thought it woudl be a little more revolutionary, but still its a useful book.