I have read a few chapters of this very beautiful book by Richard Bird called "Pearls of Functional Algorithm Design": http://www.amazon.com/Pearls-Functional-Algorithm-Design-Ric...

You should definitely check it out. If you already know Haskell and you love algorithms, that book will probably be more interesting than the Intro to Haskell book.

Also check out Okasaki's book of functional data structures: http://www.amazon.com/Purely-Functional-Structures-Chris-Oka...