The results of this study are certainly interesting and deserving of follow up research. The bigger question of the safety of cell phones, given their widespread and increasing use, also deserves further monitoring.
But this study does not mean that cell phones pose a health risk, and the effect seen does not even lend much plausibility to the possibility of risk. We are likely seeing a harmless nonspecific effect on cell metabolism.
Unfortunately, this study is easily used to stoke unwarranted fears about cell phone use.