Question
Is cremation of a dead body, permitted in Islam?
Fatwa
Praise be to Allah, the Lord of the World; and may His blessings and peace be upon our Prophet Muhammad and upon all his Family and Companions.
Cremation is strictly Haram in Islam. Also, it is Haram to break a dead person's bones, to sit on his/her tomb or to walk on it. Any of the above-named action constitutes a great crime and a major sin in Islam.
In this vein, Allah's Messenger (Sallallahu Alaihi wa Sallam) said: "Breaking a dead's bones is like breaking it as if he is alive" .
This means that there is no difference between harming a human being, dead or living. In other words, just harming a Muslim constitutes a great sin.
Allah Says (interpretation of meaning): {And those who annoy believing men and women undeservedly, bear on themselves the crime of slander and plain sin.} [33: 58].
As for killing a Muslim, Allah, The Exalted, Says:{And whoever kills a believer intentionally, his recompense is Hell to abide therein, and the Wrath and the Curse of Allâh are upon him, and a great punishment is prepared for him.} [4: 93].
Here, we state that although cremation is not like killing, but it is something near to it.
As a result, Islam prohibits cremation and even just hurting the dead.
Allah knows best.
source
http://www.islamweb.net/ver2/Fatwa/S...Option=FatwaId
side note: in the same web i read this :" ولكن لو حصلت كارثة ذهب ضحيتها عدد كثير وتعذر دفنهم أو مواراتهم عن ظاهر الأرض وكان في بقائهم على هذه الصفة ضرر على الأحياء بتقرير أهل الخبرة في هذا المجال، فلا حرج في إحراقهم حفظا لسلامة الآخرين ودفعا للضرر عنهم."
translation (i hope some body translate it better than this): if so many poeple died beacuse for ex- a disaster and they could not be buried, and it's dangerous to keep them in that way according to a report of experts.. there is nothing wrong with burning them in order to preserve the saftey of other.
wAllahu A''ALAM
Allah knows best