dtjohnson writes "A new Swedish study has found that heavy users of cell phones had a 240 percent increase in brain tumors on the side of their head that the phone was used on. The study defined 'heavy' use as more than 2,000 total hours, or approximately one hour of use per workday for 10 years. An earlier British study was previously discussed here that didn't find an increased risk, although that study covered fewer subjects and only followed one type of brain tumor for a shorter period of time. Or course, the biggest epidemiological study of all is the one we are all participating in whenever we use our cell phone. The results from that study won't be available for a while."