Andrei Lankov has a great (if short) essay about the classic Korean "ero" film MADAME AEMA at the Korea Times (here). Totally worth a read.
If you like that sort of thing, you can read a short essay about the 3S policy in KOFIC's KOREAN CINEMA book (which you can download for free here (yeah, there is a more normal link at www.koreanfilm.or.kr, but it does not seem to work with Mac computers, so I linked to Google's html cache instead. If you use PC, though, you can see the article here ).
If you are interested in urban history or more of the sports side of the 3S policy, there is a very interesting article about Seoul's urban policy and the 1988 Olympics here.
Now if someone would only write such an essay about PPONG...
Hey! Great collection of posters and stills of PPONG at the Korean Movie Database. Nifty.