Hah, I did something similar around ~2007 when I was at Last.fm and never got around to publishing it. Nice work!
This is the only example I can find lying around in my backups: http://jonty.co.uk/bits/radiohead_creep_lyricviz.png
This is the only example I can find lying around in my backups: http://jonty.co.uk/bits/radiohead_creep_lyricviz.png
Each colour is a verse, fading through the spectrum.
An unfilled arrowhead shows a transition between words in a line of a verse, a filled arrowhead shows a transition between lines.
Dunno about the arrow tips, but seems like the slowly changing colors enable you to quite easily follow the original order of the lyrics. (except if the reader is color blind)