I've read the book, but I refuse to see the movie, for many of the reasons already listed. I did a big, long research paper on geisha for my Women in Japanese History class last year, and Iwasaki, Masuda, and Dalby were valuable sources. Another good nonfiction book I used is Women of the Pleasure Quarters by Lesley Downer, which is one of the most recent sources I've found, aside from a dissertation my professor pointed out to me (which may eventually become a book).
On a related note, now that I've learned a bit of the historical background of The Last Samurai (the Satsuma Rebellion), I don't dislike it as much. Having Tom Cruise's character meet Emperor Meiji in person has got to be utter fabrication, though. I mean, I'm no expert, but I'm under the impression that no Joe Schmoe Gaijin can just waltz unannounced into a private meeting with the emperor, regardless of what he did.
I'm a robot. Bleep, blorp.