The following are links to where I got my information, along with some other useful links.SPACE.COM - Great source of the latest space news.
Chandra X-Ray Observatory - These guys study supernovas, so they know what they're talking about.
White Dwarfs and Novae - More info about Novae.
Novae and Supernovae - Pictures
Introduction to Supernovae - Exactly what the title says.
Space Art - This is where I got some of the space art featured on this site.
Offline Sources:
Chasisson, Eric, Steve McMillan. "Stellar Explosions." Astronomy Today. 4th ed. Ch.21. 1993.
"Supernovae." Microsoft Encarta. CD-ROM. 2002.