Here are some interesting links to sites for singers or teachers of singing.
The Diction Domain – Tutorials and other resources for improving your Italian, French, German and English diction.
Arizona Opera – Phoenix’s professional opera company.
The Metropolitan Opera – The premiere U.S. Opera Company.
New York Opera Forum – A lot of interesting links for classical singers.
The Desire for Hermitage by Samuel Barber. Jenny Armendt, mezzo-soprano, & Christine Parker, pianist.