Haskell is really a language very worth knowing. It does many things so different than most other languages which I really enjoy.
I’d like to use this post to mention a few really good resources for learning Haskell:
Learn you a Haskell
It isn’t finished yet, but it’s really good to start with. (Via Wadler’s Blog)
Real World Haskell
Real World Haskell is a upcoming book I really look forward to. It is freely available on its website, so check it out.
There is also a good collection of Haskell topics on Wikibooks – Programming/Haskell
Wikibook is more interesting if you already know a bit of Haskell and would like to understand it more in depth.
I liked Yet another Haskell Tutorial very much, this aims at people with a bit of background, though.
Another more recent book on Haskell is Programming in Haskell which is nice, but also quite basic IMO.
Of course there is always the Gentle introduction to Haskell
Haskell is doomed to succeed.
— Sir Tony Hoare