I recently re-encountered Project Gutenberg while looking for some online ebook content. My kids love myth & legend based tales and I was in pursuit of some stories from the Norse; the D'Aulaires book is the best (the artwork! to die for!) but far from comprehensive. Recently, the audiobooks of the D'Aulaires Greek Myths have been released - I wonder if they will do the Norse ones too soon?.
I found Norse Tales and Sketches at the Project Gutenberg site which will serve nicely. What a great site! I love the community/volunteerism aspect and hope to particpate more actively sometime in the future. If you're in the need of a light but fun ebook, check out their Wodehouse offerings. For more on Gutenberg, check out the British Library's site.