I had the honor of meeting John Vonhof, probably the world's most eminent expert on foot care for athletes, when he worked at the same aid station I did at Western States. John started out helping athletes at ultramarathons and adventure races with foot problems, learned more and more about it until he wrote a book which became the bible of athletic foot care.
My friend Geoff bought the book before Western States this year, and to his amazement did not have a single blister after running 100 miles of often steep, rocky trail.
John has now started a blog devoted to, what else, foot care and I recommend it and his book whole-heartedly.
UPDATE: fixed link to blog; sorry about that