When I published parts of this bibliography for the first time in 1997, the best online bibliography concerning the Korean history compiled by Ken Robinson was still in its infancy, as was The Harvard Korean Studies Bibliography.
Now, six years later both projects seem to be finished. The Korean History Bibliography contains a chapter Religion and Philosophy: Confucianism, in which you can find more general literature concerning Korean philosophy, but be cautious, some of the titles listed in English are only available in Korean. The Harvard Korean Studies Bibliography contains now more than 80,000 references on Korea, but is only available on CD. The majority of these references are Enlglish language works. According to the system requirements, the users unfortunately need a Macintosh or Windows machine, but I assume that the Linux users who ended up here know how to cope with this.
If you are just looking for a good starting point, I would like to recommend the following two books :