Haskell Reference at Zvon
A thoroughly indexed reference to Haskell syntax and libraries with many examples.
Haskell Tutorial
A tutorial on Haskell from Walla Walla College
Haskell Tutorial
An introduction to Haskell, including explanation of basic concepts and exercises. [Postcript]
Haskell: The Craft of Functional Programming
By Simon Thompson; Addison-Wesley, 1999, ISBN 0201342758. Edition 2, introductory textbook to functional programming in Haskell. [University of Kent]
Haskell: The Craft of Functional Programming
Descriptions, reviews, purchase source. [Amazon.com]
Monads for the Working Haskell Programmer
This short tutorial introduces monads to Haskell programmers.
Online Bibliography of Haskell Research
Provides a constantly-growing bibliography of papers, and theses, on research related to the Haskell programming language. Links to online copies of each paper are provided, where available.
The Lambda Complex
A tutorial site for Haskell aimed at programmers used to imperative languages (such as C).