Scorch 2 is the free software which lets you view, play, customise and print Sibelius scores on the Internet. (You don't need Sibelius yourself.)

The player lets you play the Sebelius format files. Each score will show you the music and words. As you play the song you can hear it on your speakers.

You are also guided through the score by a moving bar, so you can see how the words fit to the music.

The download is only 1MB and integrates with your browser. It has been virus-checked.