In an earlier article I wrote about typing Egyptian Hieroglyphs using non-Unicode systems. Now Unicode version 5.2 includes the Gardiner set of 1071 Hieroglyphs, and you can input them from the Character Palette using the font Aegyptus.
For info relating the Unicode set to the Manual de Codage (MdC) system, see this note.
I wonder if one could make some kind of useful keyboard IM for these using the OS X Custom IM Generator…
(12/1/2009) A reader has posted an experimental MdC IM .cin file here. Others are encouraged to give it a try.