Best answer comes from The Straight Dope, as usual:
"The difficulty in determining what the Koran has to say about virgins and such is establishing what the Koran says, period. Translators vary widely in their rendering of the spare and often opaque text. For example, we find the following passage in a Web-based version of Islam's holy book (www.unn.ac.uk/societies/islamic/index.htm): "Verily, for the Muttaqun [righteous], there will be a success (paradise); gardens and grapeyards; and young full-breasted (mature) maidens of equal age; and a full cup (of wine)" (An-Naba 78:31-34). Whoa, one thinks--the Kingdom of Heaven meets the Playboy Advisor! However, most other English translations, both on-line and in print, replace "full-breasted maidens" with some tame construction such as "companions." Inquiring further, we find that the Arabic word at issue is WakawaAAiba, which appears nowhere else in the Koran. The French, less prudish in these matters, usually render it as something like des belles aux seins arrondis, "beautiful women with round breasts," so I think it's pretty clear what the Prophet, or at least his stenographers, had in mind.
Nothing in the Koran specifically states that the faithful are allotted 72 virgins apiece. For this elaboration we turn to the hadith, traditional sayings traced with varying degrees of credibility to Muhammad. Hadith number 2,562 in the collection known as the Sunan al-Tirmidhi says, "The least [reward] for the people of Heaven is 80,000 servants and 72 wives, over which stands a dome of pearls, aquamarine and ruby." "
"The difficulty in determining what the Koran has to say about virgins and such is establishing what the Koran says, period. Translators vary widely in their rendering of the spare and often opaque text. For example, we find the following passage in a Web-based version of Islam's holy book (www.unn.ac.uk/societies/islamic/index.htm): "Verily, for the Muttaqun [righteous], there will be a success (paradise); gardens and grapeyards; and young full-breasted (mature) maidens of equal age; and a full cup (of wine)" (An-Naba 78:31-34). Whoa, one thinks--the Kingdom of Heaven meets the Playboy Advisor! However, most other English translations, both on-line and in print, replace "full-breasted maidens" with some tame construction such as "companions." Inquiring further, we find that the Arabic word at issue is WakawaAAiba, which appears nowhere else in the Koran. The French, less prudish in these matters, usually render it as something like des belles aux seins arrondis, "beautiful women with round breasts," so I think it's pretty clear what the Prophet, or at least his stenographers, had in mind.
Nothing in the Koran specifically states that the faithful are allotted 72 virgins apiece. For this elaboration we turn to the hadith, traditional sayings traced with varying degrees of credibility to Muhammad. Hadith number 2,562 in the collection known as the Sunan al-Tirmidhi says, "The least [reward] for the people of Heaven is 80,000 servants and 72 wives, over which stands a dome of pearls, aquamarine and ruby." "
