Created by Mark Davies, BYU.
Funded by the US National Endowment for the Humanities
Corpus del Espaņol has two different parts (both of which are now available with an English and a Spanish interface and help files):
(original, smaller) corpus that allows you to look at
historical changes and genre-based variation
the (newer, much larger) corpus that you can use to
look at dialectal variation (and have 100x as
much data for Modern Spanish).
Click on an [Info] link above
for more details.