You can have multiple playsattion network accounts on the same playstation, I have a UK, US, japan, and Korean account. If you can get a Korean friend to sign you up for the Korean network you can buy PSN cards for credits to purchase things from it. If you need to buy US games cos you only have access to the US store try www.play-asia.com its an excellent site that sells japan, US, Krean and China versions of PS3 games. Only download content is regionalised. Don't expect the Korean network to be in English because it's the Korean PSN and English is not the Korean language. All the best.
Yeah dude i feel you. I live in Korea and i have to say that everything in Korea is completely non-foreigner friendly. It seems like everything in Korea really is set up to screw over foreigners and the things that are make no sense and on practical level dont work. But its the korean way and it unfortunately will be like this for a long time.
Also it depends on the game as to what servers you join.
PSN cards can be found online with people emailing you the code.
Bad thing about imports if they are from asia often it not in english >_>
Get your Portable ID!