Phil Plait:
You may also wish to note what other things are categorized as
Group 2B possible carcinogens, including gasoline, pickled
vegetables, and (GASP!) coffee.My opinion here is that while a link between cell phones and brain
cancer cannot be ruled out, without a strong correlation and a
numerical statement about the odds, it seems very unlikely to me
that such a connection is something to worry about. I’m far more
worried about the dingus in traffic in front of me gabbing to his
friend on his phone and causing an accident than I am about me
getting brain cancer from my own.
from Daring Fireball: http://blogs.discovermagazine.com/badastronomy/2011/06/01/why-im-still-not-worried-about-my-cell-phone-hurting-my-brain/