I was wondering if anyone had the piece for piano or voice
'RUUJU no dengon (Message in Rouge)' in Kiki's delivery Service
(the one which Kiki plays over and over in her radio)

http://www.nausicaa.net/miyazaki/kiki/lyrics_rouge_jis.txt
According to this site the arrangement is done by
Lyricist/Composer/Arranger/Singer: Arai Yumi