INTERNATIONAL BUSINESS -- Cinderella, Italy Preps For Euro Ball; But as Midnight Nears, Some Business Sectors Brace for Pain
President of Italian central bank warns that next few years will be 'purgatory' for Italians as economy adjusts to European demands and adapts to single new euro currency; Italian businessmen are preparing for euro in different ways; Italian companies with markets overseas welcome euro, which will lift burden of converting lira to dozen different currencies; but Italian retail trade fears that converting cash registers and consumer behavior to new money will be costly; contrasts in expectations are being felt throughout Europe, but they are starkest in Italy, as are potential gains and wrenching costs; photos; graphs; map (L)
