Consultants Handbook - An English look at ALE.
ALE Programmers Guide - Only to be used when developing or enhancing ALE scenarios. You will require a detailed understanding of ALE and IDocs before this will make any sense.
ALE Quickstart - Short, sequential steps to setting up a simple ALE scenario.
ALE IMG - Detailed description of each configurable option available to ALE via the IMG.
IDoc interface to EDI - A little more on IDocs and EDI.