The VedaBase contains all of Srila Prabhupada’s recorded teachings found in his books, lectures, conversations, and letters. It is a searchable, database of Srila Prabhupada’s archived works, and works related to his Krishna consciousness movement. More info here: info.vedabase.com
You can download it here:
VedaBase update 2011.1.
A newer version (2013 of the Vedabase has been released. Download it here (zip, 420MB)