While I don't have any personal experience with EPIK (or JET or GEPIK) I would recommend doing a search over at the forums at Dave's ESL Cafe - Korea http://forums.eslcafe.com/korea Specifically, I would do a search under the "Job-related discussion forum". I remember seeing a multitude of posts regarding EPIK in general.
Another source is from the horse's mouth - EPIK's homepage http://epik.niied.go.kr but I'm sure you've already perused their official site.
Yes, JET stands for Japan English Teacher or something like that. It's a government program to get English teachers in public schools. I have known people who taught English in Japan through that program, so I knew what it was.