The shipping services company looks like an undervalued income play.United Parcel Service (UPS -2.67%), one of the world's largest shipping couriers, is often considered a stable blue chip stock for conservative investors. It went public in 1999, in the biggest initial public offering of the 20th century, joined the S&P 500 in 2002, and has raised its dividends annually for 15 consecutive years.But over the past three years, the stock lost more than a third of its value as it struggled with stiff competitio ...