Encyclopodia is a free software project that brings the Wikipedia, which is one of the largest encyclopedias in the world, to the Apple iPod. Encyclopodia can be installed on iPod genarations one to four, as well as on iPod Minis and Photo iPods.
This is a repost. But this is a great thing to use. Check it out.
With the glut of those cheap mp3 players here in the Philippines, too bad this won't work with those.