The Orchestra
The Orchestra: A User's Manual Percussion
A terrific resource covering many aspects of the percussion. Most explanations are made with video and audio clips of members of the Philharmonia Orchestra.
Other
Vic Firth: Educator's Resource Library
This website is a cornucopia of resources for percussion instruction. There are videos, audiocasts, podcasts, interviews with talented percussionists. Please check out this website is you are interested in any aspect of percussion.