The Amharic writing system is an abugida, where each consonant has a base shape, and vowels are represented by modifications to that base. A common way to display the characters for learning is in the "HaHu" table, so called because the first 2 characters of the first row are pronounced "Ha" and "Hu".
HaHu4u is a simple web app that helps you learn the HaHu by hearing the sounds and seeing where the characters belong in the table.