There's a wealth of information available!
http://www.lib.washington.edu/music/mushist.html
http://www.carnatica.net/appreciation-main.htm
http://www.andante.com/reference/index.cfm
http://www.classical-composers.org/
http://w3.rz-berlin.mpg.de/cmp/classmus.html
Music History:
http://www.ipl.org/div/mushist/
http://library.thinkquest.org/15413/history/music-history.htm
Internet Radio:
http://www.beethoven.com/
http://classicalwebcast.com/usa.htm
http://classicalwebcast.com/europe.htm
http://classicalwebcast.com/rest.htm
http://www.live365.com/stations/ryanmaryopera
http://www.operaradio.com/
http://www.operadio.com/
Libretti:
http://libretto.musicals.ru/index.php?language=1
http://opera.stanford.edu/iu/librettim.html
The Rough Guide To Classical Music ("This book is invaluable for those who have a limited knowledge of classical music and want to expand their listening repertoire."):
http://www.amazon.com/Rough-Guide-Classical-Music-Reference/dp/1843532476
Classical Music Reference Library:
http://www.alexanderstreetpress.com/products/bakr.htm