Internet History Sourcebooks Project
Fordham University: Medieval Sourcebook: Rubaiyat
Fordham University gives a complete version of the 500 verses of the Rubaiyat translated by E.H. Whinfield.
Massachusetts Institute of Technology
Mit: Internet Classics Archive: The Rubaiyat
This site from the Internet Classics Archive contains a copy of The Rubaiyat by Omar Khayyam. Also contains link to other people's comments about the poem.