From the Evolution Directory (EvolDir) via Twitter.
Having just discovered my Kindle app (mine's on an Android tablet,
they are available for most/all tables and smart phones) I took a look
at what's available at Amazon's Kindle Store - and noticed *many*
books with a $0.00 price tag - including:
Insectivorous Plants by Charles Darwin (Kindle Edition - May 1, 2004) -
On the Origin of Species By Means of Natural Selection, or, the
Preservation of Favoured Races in the Struggle for Life by Charles
Darwin (Kindle Edition - Mar 1, 1998)
The Descent of Man by Charles Darwin (Kindle Edition - Mar 24, 2011) -
Lots more! They may be interesting and/or useful.