Plainsong
www.schuyesmans.be/gregoriaans
Information about Gregorian chant notation

Tonic sol-fa
http://ourworld.compuserve.com/homepages/Neil_Hawes/theory39.htm
Information about the sol-fa system

Notation
www.lessontutor.com/eesMusic1.html
Elements of music notation with activities

Sibelius software
www.sibelius.com
Find out more about Sibelius software