if you're going to seoul, you'll be fine. if ou're aian or white, you'll be fine. if you have money, you're going to have a lot of fun. go to itaewon, it's a district of seoul where there are a lot of foreigners. Just get on a train and get off at itaewon.
You should get some traveller's stuff at the airport when you land, like maps in english, etc. You'll find some people who speak English, but a lot of Koreans are wary of strangers.
BTW, the dollar is actually strong against the won right now, cause the korean economy is shit, so you'll actually be getting a really good exchange rate.
If you wanna explore the hip korean places, then go to abgujongdong, myoungdong, etc, but try to go with a korean friend. there's lots of nice restaurants and clubs in that area.
Have fun! Nobody eats dog in seoul, that's like telling people to beware of cannibal rednecks in america.
have fun : )