I found a book that is so awesome it deserves its own thread.
Foot treatment, blister prevention and treatment, orthotics... all that stuff and a ton more come up often in the forums. This book addresses everything in AMAZING depth.
If you haven't read it, you probably should.
Check out "Fixing Your Feet" by John Vonhof. (No, I don't have any vague notion of affiliation with the author or publisher.)