Pocket Wikipedia, hand-checked selection from Wikipedia which is about the size of a fifteen volume encyclopaedia (24,000 images and 14 million words). The selection was made by Schools Wikipedia and is available for download here. This application it's a freeware software, works on PocketPC, Windows and Linux.

Pocket Wikipedia was created to work on PocketPC systems. After that was ported on Windows and Linux systems. Pocket Wikipedia on PocketPC can be download here

I haven't tried this application , the 1st link might be a new version of the database