Finale NotePad is available as a free download (upgradeable to fuller, paid-for versions) for Mac and PC (Finale NotePad 2007 for Mac OS 10.3.9, 2008 for 10.4+). I read about this in an earlier thread thread.cfm?threadid=50269#761621 . It did what I wanted (melody line with related lyrics, full text below) but seems to be capable of much more. The spec suggests that midi input and output, and conversion to staff notation, are all possible.

Ross