

An Introduction to Lambda Calculus and Scheme - paulgb
http://www.jetcafe.org/jim/lambda.html

======
gnosis
A much more thorough, free book along similar lines is:

 _"An Introduction to Functional Programming Through Lambda Calculus"_

<http://www.macs.hw.ac.uk/~greg/books/gjm.lambook88.ps>

There's also this:

 _"Introduction to Lambda Calculus"_

by Henk Barendregt , Erik Barendsen

<http://citeseer.ist.psu.edu/barendregt94introduction.html>

