Ethiopic
The Ethiopic syllabary is is the writing system used for several languages of Ethiopia and Eritrea, including Amharic, Tigrinya, and the liturgical Ge'ez language.
Fonts
The Resource page for Ethiopic fonts and input methods at wikipedia is agood place to look.
Abyssinica SIL TrueType fonts are included in Debian and other Linux distributions in the package ttf-abyssinica-sil.
Keyboard
Ethiopic keyboard package for Linux
Typing in Harari (Ḣarari / ሐረሪ)
Unicode
Please note that there may be additions to the Ethiopic characters in the Unicode standard in the coming years, as more linguistic work is done.
PDFs of multiple versions of The Unicode Standard are available.
This document contains some information about Ethiopic
There is a mention of Ethiopic on pages 4 and 5 of this document.
There are code charts for three blocks of Ethiopic characters.