According to BBC News, Wikipedia are to start putting articles on CD and selling them for offline at $13.99 (£7). Whilst this is probably good news for third world countries (charities might foot the bill) if you want to do something similar yourself, I’d recommend doing it for free with Webaroo…
Yay for Webaroo! A student of mine showed me this wonderful tool. He turned to it because I've banned student laptops from the WiFi network (too much mischief).
Webaroo didn't get all the articles, but he was able to see many articles' pages formatted and with images.
Beware! Total download is nearly 4.5 G.
Webaroo rocks, IMHO, for students. No great-time-wasting distractions of the Web and much of the content of Wikipedia.