Today I registered for the free at home Korean classes offered by the Seoul Multicultural Support Centers (다문화가족지원센터) http://english.seoul.go.kr/lh/support/scof4.php. Note that the website does not list all the centers. I had to go to the center and bring my ARC and Family Relationship Certificate (가족관계중명서). Presently there are a number of people ahead of me so it will be a couple of months before classes begin. The classes last for 1 year for a total of 40 weeks and are twice a week, for two hours a class. Once at your local center you can simply say I'd like to register for the door-to-door Korean classes ( 가정방문 한국어 교육 등록하고 싶습니다).
There are two semesters: August to December and February to July.
For those of you living outside of Seoul here is the Danuri Multicultural Family Support Center Website: HERE
Information regarding the first day of class HERE
Three months into classes HERE