Learning Lambda Calculus

What are some good online/free resources (tutorials, guides, exercises, and the like) for learning Lambda Calculus?

Specifically, I am interested in the following areas:

• Untyped lambda calculus
• Simply-typed lambda calculus
• Other typed lambda calculi
• Church's Theory of Types (I'm not sure where this fits in).

(As I understand, this should provide a solid basis for the understanding of type theory.)

Any advice and suggestions would be appreciated.

Solution 1:

Alligator Eggs is a cool way to learn lambda calculus.

Also learning functional programming languages like Scheme, Haskell etc. will be added fun.

Solution 2:

Recommendations:

1. Barendregt & Barendsen, 1998, Introduction to lambda-calculus;
2. Girard, Lafont & Taylor, 1987, Proofs and Types;
3. Sørenson & Urzyczyn, 1999, Lectures on the Curry-Howard Isomorphism.

All of these are mentioned in the LtU Getting Started thread.