Here you can experiment with Lilypond and even download PDF and MIDI version of your own Lilypond files.
To get started, see what happens if you enter:
\version "2.10.33" \relative c' { c c g'( e)} \addlyrics{Hel -- lo world __ }
\relative c' { c c g'( e)}
\addlyrics{Hel -- lo world __ }