Operabase

Sheer size makes this online database essential for online opera lovers. Built up around opera performances all over the world, it includes a search tool that allows you to find a performance or artist from more than 16,000 opera performances since August 2005. You can also find opera houses by name or address, as well as track down festivals worldwide. Despite its bulk, it's not unwieldy, loading up nice and swiftly. Special features include Timeline where you can find new composers and music by looking at comparable works and writers and a section of city guides for operaphiles.

For those not satisfied by Operabase, the subscription area of the site - operabase professional - builds on and extends the archives, toolsets and software of Operabase, allowing you to search through the archive of 155,000 opera performances (over 20,000 artists), of the last ten years.