Now, you can take this with a grain of salt if you like, because I work in the cellular industry..
Cell phones give off what is called non ionizing radiation. In other words, it's not the bad stuff that tears through you and destroys everything in it's path. Essentially it is of a similar frequency and properties as the energy used in your microwave.
Egads you say! Using my cell phone will pop my brain like a bag of microwave popcorn!!
Perhaps. But modern CDMA digital handsets operate at less than half a watt of output power. Compare that will 700-1000 watts on the inside of a microwave. You'd have to hold that bad boy to your head for a long long time to ever heat up anything inside.
There have been no conclusive studies that show non ionizing radiation of the levels in cell phones cause any problems in humans.
BTW...most handsets warm up over the course of a long call. This is not radiation. It's the battery discharging and getting warm. No radiation