I am a HUGE classical music fan; in fact, while I'm working I listen to various classical music radio stations online with my Apple Quicktime player. Here's a few great classical music sites that you can use to listen to classical music, find a good classical music radio station, or learn more about classical music history.

• Musipedia: The Open Music Encyclopedia: "A searchable, editable, and expandable collection of tunes, melodies, and musical themes."
• BBC Classical Music Online: Find classical music news, listen to classical music online, or find classical music and concerts in your area (the UK).
• Classical Music for Beginners and Experts Alike: Aaron Green has a phenomenal classical music information site here - I visit his site often.
• Classical Music - Alphabetic Catalog: Georgetown Prep's A-Z catalog of everything classical music.
• Classical Online Radio Stations in the US: The very first one on this list is the one we listen to in the car, in the house, online, etc.
• PublicRadioFan.com: You can find a classical music station here for anywhere in the world. Use the Station Finder for best results, then narrow down your search.

This is just a partial sampling of what is out there in the world of classical music online. Please feel free to add your favorites in the comments section below.