It is believed by some radical Muslims that suicide killers will receive sexual rewards in heaven. Other Muslims disagree with them and say it is a sin to commit suicide and therefore they'll not enter paradise according to this Hadith (Prophet's sayings) :

Bukhari Volume 2, Book 23, Number 445

Narrated Jundab the Prophet said, “A man was inflicted with wounds and he committed suicide, and so Allah said: My slave has caused death on himself hurriedly, so I forbid Paradise for him.”

But some Muslim apologists say that while suicide is forbidden in Islam, martyrdom for an Islamic cause is praised and welcomed according to the Quran: (3:169)

“Do not consider those killed [while engaging] in God’s cause dead. Rather, they live with their Lord, who sustains them!”

So, those who have died while blowing up innocent women and children are considered martyrs or suicide killers? I believe a peace-loving Muslim will call these people murderers whereas a radical Muslim will call them "martyrs". 

Anyway, where does this teaching that suicide killers will receive 72 virgins in Paradise come from? It is derived (loosely) from the following Hadith:

Sunan al-Tirmidhi Hadith 2562
"It was mentioned by Daraj Ibn Abi Hatim, that Abu al-Haytham 'Adullah Ibn Wahb narrated from Abu Sa'id al-Khudhri, who heard Muhammad saying, 'The smallest reward for the people of Heaven is an abode where there are eighty thousand servants and seventy-two houri, over which stands a dome decorated with pearls, aquamarine and ruby, as wide as the distance from al-Jabiyyah to San'a."

 Watch the interviews of these failed suicide bombers: