> P.S.: Also welcome is a "Lambda-Calculus for Dummies" recommendation
>       on literature (or web-links). ;-)

Crash Course:

http://www.cip.physik.uni-muenchen.de/~tf/lambda/aei

And furthermore - as you are german anyway:

http://www.cip.physik.uni-muenchen.de/~tf/lambda

I would not say that this material is of sufficiently high quality to 
publish it in a book (I consider it to be only ~90% correct, for example), 
but I think it nevertheless is reasonably okay.

-- 
regards,               tf@cip.physik.uni-muenchen.de              (o_
 Thomas Fischbacher -  http://www.cip.physik.uni-muenchen.de/~tf  //\
(lambda (n) ((lambda (p q r) (p p q r)) (lambda (g x y)           V_/_
(if (= x 0) y (g g (- x 1) (* x y)))) n 1))                  (Debian GNU)