Now that more states are getting Amazon to agree to collect sales tax, SmartMoney reports that their next target may be digital media, including eBooks. Deloitte forecasts that U.S. eBook sales will reach $3.19 billion by 2015, an amount that's very enticing to state and local governments. Nearly half of all states already collect sales tax on some digital content, but the rules vary by state. For example, Idaho, Kentucky, Vermont, Washington and Wisconsin collect sales tax on eBooks, digital music and movies. Texas, Arizona and Maine also do so by defining digital goods as "tangible personal property" subject to sales tax. Florida exempts eBooks from sales tax, but not digital movies or television shows. New Jersey collects sales tax on digital content, but not apps.