The following items provide detailed information about the language Haskell:

Home Computing GHC	Not only do these guys provide a useful CD (only $2!) that contains many programs used in our courses, but they also allow you to download these programs and provide support for getting them working.
Haskell	Home page of the Haskell system used in this course
Haskell Report	Haskell 98 Language and Libraries
The Glasgow Haskell Compiler	Home page of the Haskell compiler used in this course
The Glasgow Haskell Compiler User's Guide	All you ever wanted to know about GHC - and more!
Haskell Reference	Haskell reference at ZVON
A tour of the Haskell Prelude	Bernie Pope's annotated Haskell Prelude; there are some small deviations from the standard.
A tour of the Haskell Syntax	Arjan van IJzendoorn overview of Haskell syntax - very handy for revision
Haskell mode for xemacs	This is what Tim uses in lectures. You can use it at home if you follow the installation instructions carefully.