Here are some cooking classes that O'ngo Food Communications is running for travellers and residents of Seoul. http://www.seouleats.com/p/korean-taste-tours-and-korean-cooking.html
I found a couple more cooking schools in Seoul for visitors via wikitravel. I haven't checked them out, but they sound good.Via wiki travel
CookingKorea's cuisine is known the world over for being healthy and spicy. Learning how to make Korean dishes such as kimchi and bulgogi can be messy, but a lot of fun! Fortunately, there are several cooking institutes throughout Seoul catering to foreign tourists.
- O'ngo Food Communications Culinary Academy. Learn how to make Korean favorites such as Spicy Chicken Barbecue (Dakgalbi), Kimchi, Seafood Pancake, and bibimbap. Located in Insadong at Jongno 3-ga Station Exit 5. 02-3446-1607. Located at the former Han Jeong Hye Cooking Studio. Lessons cost between 55,000 and 100,000 won.
- Closed. Now O'ngo Food Communications Culinary Academy. Han Jeong Hye Cooking Institute (한정혜요리학원), (Jongno 3-ga Station, Exit 5. Five minute walk), ☎ +82 2 742 3567, . For class times, inquire in advance. At Han Jeong Hye Cooking Institute you can learn how to prepare Kimchi, Bulgogi, and Bibimbap. Lessons cost between 60,000 to 100,000 won. edit
- Institute of Korean Royal Cuisine(궁중음식연구원), (Anguk Station, Exit 2. 20 minute walk), ☎ +82 2 744 9092, 3673 1122, . For class times, inquire in advance. As the name implies, you learn how to prepare royal cuisine, as well as rice cakes and hangwa (Korean Cookies). Lessons cost between 50,000 to 100,000 won. edit
- Son's Home(손즈홈), (Yeoksam Station, Exit 3. Five minute walk), ☎ +82 2 562 6829, . 10:30 AM to 1:30 PM, and 5:00 PM to 8:00 PM (Groups of at least 5 only). Closed Wednesdays.. Son's Home specializes in teaching Kimchi preparation. Lessons are 70,000 won for adults, 60,000 for children under 15. edit