Seoul Metro has an interactive subway map so you will know exactly how long your trip will be. It has an English site and both the site and the actual subway are incredibly easy to navigate.
iExplore.com has general Do's and Don'ts for traveling in South Korea.
GenkiKorean is an awesome (and dare I say, fun?!) site for learning Hangul- the Korean language. The games are fun, but warning: you WILL get yelled at in Korean if you miss answers.
