Even as more foreigners are picking up the iPhone and iPad, I find myself sticking with an iPod Touch - and a full-fledged netbook computer better able to do the heavier lifting. There are times when one or the other is preferred; in this case, looking up the subway lines is an easy job for the iPod Touch.
Enter this free app - SeoulMetroTour Lite - into the mix. After starting the program, you can tap your way into a Seoul subway system map completely in English. Tap on Sights (as above) to highlight a number of tourist-friendly destinations.