Islam

General Reference
Islamic Reference Materials
Sites about Islam
Religion of Islam

Qur'an and Commentaries
The Holy Quran. An indexed version of the Qur'an translated by Yusef Ali.
The Holy Quran. These files are electronically scanned versions of M.H. Shakir's translation of the Holy Qur'an.
Sunnah and Hadith

Islamic History
Internet Islamic History Sourcebook
History of Islam

Sunni and Shi'a Islam
Sunnah of Muhammad Islamic Page
Medieval Sourcebook: From The Sunnah
Shia Islam

Sufism
Sufism -- Sufis -- Sufi Orders: Sufism's Many Paths
Bawa Muhaiyaddeen Fellowship