From the Quran and the Hadith:
"A slave, the property of another, has no power over anything" (Sura 16.75)
"Your slaves are your brethren upon whom Allah has given you authority" (Hadith 3.721)
From Islamic scholars of ancient times:
"Slavery is justified... it is not permissible to enslave a free Muslim, but it is lawful to enslave the infidel, and it also makes it lawful to take his offspring into captivity." (Mufti Ibn Timiyya, Vol 31, p 380)
"Muhammad had many male and female slaves. He used to buy and sell them, but he purchased more slaves than he sold, especially after God empowered him by His message, as well as after his immigration from Mecca. He once sold one black slave for two. His name was Jacob al-Mudbir. His purchases of slaves were more than he sold. He was used to renting out and hiring many slaves, but he hired more slaves than he rented out." (Ibn Qayyim al-Jawziyya, "Zad al-Ma'ad", Part I, p. 160),
"These are the names of Muhammad's male slaves: Yakan Abu Sharh, Aflah, 'Ubayd, Dhakwan, Tahman, Mirwan, Hunayn, Sanad, Fadala Yamamin, Anjasha al-Hadi, Mad'am, Karkara, Abu Rafi', Thawban, Ab Kabsha, Salih, Rabah, Yara Nubyan, Fadila, Waqid, Mabur, Abu Waqid, Kasam, Abu 'Ayb, Abu Muwayhiba, Zayd Ibn Harith..." (Ibn Qayyim al-Jawziyya: "Zad al-Ma'ad" Part 1, pp. 114, 115, and 116)
The following episode is reported by all ancient chroniclers of Mohammed. The two female slaves of Mohammed captured in battle and forced to have sex with him where Maria (Christian) and Rayhana (Jewish). After the battle with the Jewish tribe of Quraiza, Rayhana was crying and mourning for her husband's death by the order of Mohammed, but in the same night that Mohammed massacred her tribe in cold blood, he forced himself upon her.
(I was not there: I am just quoting holy Islamic chroniclers, studied in all madrasa of the Islamic world).
From Ahreeman's "History of Slavery in Iran":
"Slavery was basically non existent in the Persian Empire before Islam. Persians... never open practiced slavery... They were anti slavery and the best example was the released of 42,000 Jews from slavery in Babylon by Cyrus The Great... When Islam came to Persia, slavery came with it. Arabs took many Persians as slaves, basically young boys and girls. Young girls would be forced to become concubines and young boys were forced to become "toy boys". Strong and bigger boys would become slave laborers for Muslims. Persian women were sent by tens of thousands to the Arabian Peninsula... During the 222 years of Arab occupation, Iran imported slaves from Africa such as Ethiopia... The term "Nokar-e Khan-e Zad" (house nigger) is a popular Persian term which originated in those times. Slavery was a norm during the 222 years of Persia's occupation under Islam... When Yaqoob Leis Saffarid liberated Iran, the tradition of slavery started to fade away."
In the early stages of Islam, slaves were used in the "American" way. In southern Iraq, they were put to work in large quantities to clear the salt crust for agriculture and plantation labor. In the ninth century, following a slave rebellion that caused much damage in Baghdad, there developed a reluctance to allow large concentrations of slaves for plantation agriculture, and slavery was limited to domestic use. Like it is today in Saudi Arabia.
I forgot Mauritania. The Anti-Slavery Society's findings (1982) and those of Africa Watch (1990) estimate 100,000 slaves and additional 300,000 half-slaves, all of them black, still being held as slaves by Arabs in Mauritania.
The Saudi ambassador to the USA, Prince Bandar, is the son of a black slave family originally sold by Sudanese slave traders to a wealthy Saudi Arabian family.
I suggest you read the "Arab Human Development Report 2002", written by a group of Arab intellectuals (many living in Arab countries). They are more objective than you in confronting the problems of the Arab world.
Bottom line: the Quran tolerates slavery. Mohammed himself practiced and tolerated slavery.