At a tree-trimming party at his Chicago co-op apartment, Eric Spanitz supplied seasonal music, a mix of Bing Crosby and "A Charlie Brown Christmas," which issued from a certain well-known compact portable electronic device--a mobile phone.About a year ago Spanitz, a professor of management at Lake Forest University in Illinois and a business consultant, finally decided to buy a phone and a music player, but he didn't want to carry two devices. Instead he bought a Sony Ericsson W800i Walkman phone that combines both.   Read more...