even relatively liberal modernist scholars like Yusuf al-Qadawi says martyrdom operations are permissable under certain circumstances.
it depends upon intention, if the intention is depression and to end life or anger or such like then yes it is clearly haram but if the intention is to kill the enemy and only use your body as a means of delivering the device then many ulema say it is impermissable.
remember sister actions are put by intentions, if someone is depressed with life and wishes to end it taking some enemies with him his intention was suicide but if some pious brother or sister hoping for the highest reward from Allah wishes to take out the enemies of Allah and realises that the most effective way of doing this is taking them with them then that is different.
besides,
those scholars who say such things are not allowed automatically have an advantage... they can speak as they like and not risk arrest, imprisonment and being flown by plane to morocco or syria to be buggered and tortured with electrodes and knives at george bush's will.
you might notice most of the mujahadeen scholars are either in prison, dead or in the battlefield and not really accessable to you or i.
even if martyrdom operations are permissable this does however not make this particular operation allowable, they're are many different factors to look into it which could still make it haram but i just refuse to condemn it until i have looked at all the evidence in enough detail.
assalaamu alaykum,
Daw'ud