Thanks to Roberto for bringing this to my attention. This is a video overview of Garo magazine, entitled "Garo no Jidai wo Yomu" (Reading the Era of Garo). Originally uploaded in August, 2009. It's broken up into 5 parts.
If you want to learn more about Garo. It is in Japanese without English subtitles, but you can fastforward to the parts that you think are the most interesting.