Whether you're new to Sibelius or want to discover some helpful features, check out this series of web videos.

eMusicTheory.com provides online tools for teachers and students of basic music theory, everywhere.

Welcome to the 8notes.com online Music Theory course. 46 Lessons introducing you to the most important concepts of music theory.

The MIDI Basics page from TweakHeads Electronic Musicians Cafe. Has a good overview of MIDI, but also a sidebar to information on many other music technologies.