I know this isn't a "website", per se, but I need to share Dudamel conducting the fourth movement of Dvorak's "New World Symphony" since I just bookmarked the listening map. This is such a wonderful performance, and it demonstrates how crucial the conductor is in coercing a certain sound from the performers!
Carnegie Hall made an animated and interactive listening map for all four movements of Dvorak's "New World Symphony" and it's wonderful! I use this with my sixth graders during our music history unit!