I noticed that there seems to be no easy way for Haskell programmers to use bcrypt, so I made something similar, with the goal of making good security trivial. It's just a slick API around PBKDF1, with painless support for increasing the number of iterations:

http://hackage.haskell.org/package/pwstore-fast

Now I've just got to persuade a few people to switch away from insecure methods.