Currently, there is very little evidence of health risks from use of cell phones.
One of the best studies does show an increased death rate in heavy users of cell phones - these deaths come not from cancer, or any other disease but from road traffic accidents.
Apart from the increased risk of death from road accident, no one has yet managed convincingly to show any other health effects. Further, experiments on animals have shown equivocal effects only at huge exposures (thousands of times that obtained from cell phone usage). Finally, there is still no orthodox theory that predicts damaging effects from cell phone emissions.
In short, if there is a health risk, no one has yet found it. This doesn't mean that there isn't a risk, but considering that scientists have looked hard for one, it is likely to be small.
I, myself, am willing to take the risk, and keep using my cell phone.
Just to finish, there is one last twist to the tale: some headset/phone combinations have been shown considerably to increase the emission exposure to the wearer.