Librivox has just released a new recording of Twain's "In Defense of  
Harriet Shelley" at:
http://librivox.org/in-defense-of-harriet-shelley-by-mark-twain/

Mark Twain pulls no punches while exposing the "real" Percy Shelley in  
this scathing condemnation of Edward Dowden's "Life of Shelley". Even  
though, as Twain writes, "Shelley's life has the one indelible blot  
upon it, but is otherwise worshipfully noble and beautiful", Twain  
shows how Shelley's extra-marital conduct might easily be seen to have  
been the cause of his wife Harriet's suicide.

The recording is also available at:

http://www.archive.org/details/harriet_shelley_jg_librivox