HARMONY version 3.2.4 (soon to be released) lets you create music in three ways : Point and click with the mouse, type the notes at the keyboard, or let it generate a tune automatically!

Personally, I still find it easiest to write the abc in a text editor and import, though.

HARMONY now supports multiple voices, multiple staves, synchronised lyrics, MIDI instruments AND controls (so you can bend notes, etc), and will generate chords or harmony voices.