Ear piece, bluetooth. Many cell phone users use a hands-free blue tooth earpiece and set the phone down. Since radiation normally decreases with the square of the distance between objects, some cell phone users hold the phone farther away or use the speaker phone option. Personally, i like the ear piece best. Please note that no definitive proof has linked cell phone radiation to damage yet. Be careful driving!
Cell phone. Cell phone irradiation has not been proven to be a significant problem. The best way to resolve your issue is to not use a cell phone. If this is impractical for you, then limit your use of the phone.
Use it less. While there's no good evidence that the radiation from cell phones is harmful to anyone, if you want to reduce your exposure just use your cell phone less, or get a hands-free headset. Keep in mind that the big danger from cell phones has nothing to do with radiation-- it's driving while talking and texting. Adults and children are routinely killed by distracted drivers.