Thank you very much for all your views.
As advised, I'll get one with less radiation emitted and use a hands-free.
BTW, I find the links below are useful for checking the radiation level of the cell phones:-
http://reviews.cnet.com/4520-6602_7-5020355-1.html
http://www.sarshield.com/english/rad...rt-samsung.htm
http://www.cellphoneradiationprotect...level-01.shtml