Story from the BBC that was highlighted on BoingBoing.net August 4th: Bibliomulas, or mule libraries, and how they serve to encourage reading in Venezuela - http://www.boingboing.net/2007/08/04/mule_library.html .
Direct link to the BBC story: Venezuela's four-legged mobile libraries
http://news.bbc.co.uk/1/hi/programmes/from_our_own_correspondent/6929404.stm

Additional story on the O'Reilly Radar: Books to Villages, Libraries on Mules http://radar.oreilly.com/archives/2007/08/books_to_villag.html