Talk to Me in Korean (Korean Word of the Day):
http://www.talktomeinkorean.com/
Omniglot (Alphabet, pronunciation, writing, and language):
http://www.omniglot.com/writing/korean.htm
Learn Korean.com
http://www.learnkorean.com/home/index.asp
Learn Korean.net
http://www.learn-korean.net/
Korean Class 101
http://www.koreanclass101.com/
*This site is a paid site*
LiveMocha (for Korean and other language learning)
http://www.livemocha.com/
KBS World Radio Let's Learn Korean
http://rki.kbs.co.kr/learn_korean/lessons/e_index.htm
Sogang University Korean Language Program
http://korean.sogang.ac.kr/
My Linguistics (Korean learning apps and commentary)
http://mylinguistics.wordpress.com/
Korean Wiki Project
http://www.koreanwikiproject.com/
There are many, many sites that can teach you whatever you're wanting to learn in Korean, these are just a few samples. Happy learning!
