One tip: hope you don't try the bottled pre-made baechu kimchi sold in supermarkets. Well... you can try, but don't say I didn't warn you, the preservatives and the taste is kinda too generic ^_^
The real just-prepared kimchi is the best. Pickled, yummy and spicy but somehow sweet in its own way. But it's South Korea - there are more versions of kimchi there than you can shake a stick at.
Look for restaurants that specialize in kimchi, or at least serves in-house kimchi and you'll be in for a treat. Well, most you'll encounter will be of the baechu kimchi variety, but if you encounter other varities, you're in luck ^_^