MapReduce from the basics to the actually useful (in under 30 minutes) Mike Miller supplements his appearance on the NoSQL Tapes with this posting on mapreduce.
Said to be followed by a posting with killer visualizations. Will keep watch for it.
Correction: As posted, attributed the posting to “Stefano J Attardi,” the producer of the NoSQL tapes. Corrected 11 February 2011 to attribute the posting to Mike Miller. Apologies.