The Orchestra
The Orchestra: A User's Manual Violins
A wonderful resource covering many aspects of the violin. Most explanations are made with video and audio clips of members of the Philharmonic Orchestra. Be sure to check out the players tips and tricks section.
Other
Choral Resources: Choral Rehearsal Techniques
A vast amount of advice and help is found at this site concerning choral rehearsal techniques. From general advice to specialized strategies you are likely to find something useful.
Other
The Violin Site: Bow Arm Exercises
Many exercises and techniques for the bow arm are explained on this site with the use of music studies and videos. This is a good resource that helps explain the proper techniques for using the bow arm properly.