To view these scores you will need Scorch, which is a free internet plugin. To install Scorch, please go to:
Mac OS 10.3 or ealier and Windows 98, ME, 2000 - http://www.sibelius.com/cgi-bin/download/get.pl?com=sh&prod=scorch4
Mac OS 10.4 or later and Windows XP and Vista - http://www.sibelius.com/cgi-bin/download/get.pl?com=sh&prod=scorch 

Once the music appears simply click on the score to begin playback. To stop and start from a particular bar, again, click on the music.