By Brian X. Chen March 3, 2010 | 4:04 pm | Categories: Phones While visiting Japan in September, 26-year-old Stanford graduate Eddie Kim picked up a book about coding Android apps because he thought it might be a fun hobby. Little did he know that six months later, his casual creation would earn him more money than any of his full-time jobs. Kim, a former Volkswagen engineer and co-founder of San Francisco-based startup Picwing, now earns $13,000 each month off an Android app called Car Locator (right), which helps users find their parked cars. Kim’s app, which he sells for $4 per download, took him only three weeks to code. “I thought about making an app for the iPho...