There are a number of books that have been written by expats living in South Korea, and this is the place to find them.
Expat Evan has written a great eBook showcasing some of Korea's most popular food offerings. In it, Evan highlights the most popular Korean foods according to Expats living in Korea, and Koreans themselves. The eBook covers 25 of the foods that you have to try while living in South Korea. Best of all, it's available for free on his website . Look for the link just below each of his articles.
BUG 'zine' -a series of self-published, self-promoted zines that contains some of the finest writing on the underground art and cultural scene in Korea - amazing interviews with a Gisaeng, a PPong-jak artist, etc. Especially recommended are Vol. 1 and 3 (interviews with Korean cultural notables) and Vol. 5(interviews with foreigners living here)
Where to buy them? Unfortunately they are out of print, but maybe if you 'bug' Kyobo bookstore enough, they might bring about a reprint. The author, Scott Burgeson, still lives in Seoul and is purportedly working on a sixth volume.
His recently relaunched site can be visited at: http://www.kingbaeksu.com/
Interview with J. Scott Burgeson available at http://www.triplopia.org/inside.cfm?ct=585