Scheme

A Scheme style guide R5RS Scheme Report (language standard) web site and html standard
R6RS Scheme Report web site and html standard

Racket Guide
Racket Reference
All Racket Documentation

MIT Scheme web site
MIT Scheme Reference as html or pdf
MIT Scheme User Manual as html or pdf

Structure and Interpretation of Computer Programs (SICP) web site, html version, and other formats

Haskell

The haskell.org web site
Hoogle, a Haskell function search engine

Learn You a Haskell for Great Good!

A fairly gentle introduction to Haskell—this is a good place to start.

Real World haskell

This book is oriented towards practical applications of Haskell and includes examples that involve building GUIs and calling web APIs.

Parallel and Concurrent Programming in Haskell

An advanced look at techniques for parallel and concurrent programming in Haskell.

The Haskell Road to Logic, Math and Programming

Learn math and logic using Haskell as the vehicle.

A list of Haskell tutorials on the Haskell wiki
Write Yourself a Scheme in 48 Hours (in Haskell)
Write You A Scheme, Version 2.0

Prolog

A Concise Guide to Prolog, from David Matuszek at UPenn.
Learn Prolog Now!
The GNU Prolog Manual
John R. Fisher’s Prolog tutorial

Standard ML

SML/NJ
Standard ML tutorial
Bob Harper’s Standard ML book