General Sources
    The
Online Medieval and Classical Library
   
Yahoo! Mythology and Folklore directory
Greek
   
Hesiod:  The Theogony.  translated by H.G. Evelyn-White (
Loeb Classical Library, 1914).
   
Apollodorus:  Library of Mythology
Welsh
   
The Mabinogion unabridged, translated by Lady Charlotte E. Guest (1812-1895)
   
The Mabinogion:  introduction and a few tales, by Jeffrey Gantz.
   
Catholic Encyclopedia: MABINOGION
   
Bibliography of the Mabinogion
Norse (in alphabetical order)
    Beowulf:
       
Beowulf Resources (includes text)
        Beowulf
(in Old English), Klaeber edition
       
Beowulf translated by Francis Gummere
       
The Adventures
of Beowulf (a free translation by David Breeden)
        Electronic
Beowulf
        Beowulf
Bibliography 1979-1994
        Beowulf
: Reference
   
Heimskringla or The Chronicle of the Kings of Norway by Snorri
Sturluson (c. 1179 - 1241).
        English translation by Samuel
Laing (London, 1844).
    Nibelungenlied:
       
The Nibelungenlied.  c. 1200 AD (?).  ranslation by
Daniel Bussier Shumway, 1909.
       
The Nibelungen:  the historical truth
Njal's Saga. Icelandic, 13th century A.D. Translated by Sir George W. DaSent (1861).\
   
Volsunga Saga  with Excerpts from the Poetic Edda. 
Icelandic, 13th century AD.
        translated by William Morris
and Eirikr Magnusson ("The
Story of the Volsungs", 1888).
Mythology and Religion, various resources: