How do I get two 'Kingdoms at War' accounts on one iDevice so that both are fully playable?

Kingdoms at War (KaW) is a game for iPhone/iPod and PC. You're limited to one account per iDevice, and one PC account, but there is a way to have both accounts playable at the same time on a single iDevice. I know that it requires a jailbroken iPhone (which I have), but I do not know what else must be done. Any help would be much appreciated.