HAVE HEART St. Louis Cardinal shortstop David Eckstein shares his inspirational story of overcoming his 5-foot-7 stature to becoming the 2006 World Series MVP.   David's first-person prose reads like a conversation that is really a peptalk on life. He shares his ups and downs, along with colorful family and action photos, and tells how he beat the odds to become a professional baseball player.  The book also details the family dynamics that have helped the Ecksteins overcome kidney failure in three of the five children and their father.