I don't think there are any official cases yet in USA stores, in other words cases made specifically for the KT. I'm not sure where you live, but i read in one of the threads here that Borders is supposed to start stocking some in late July. I would be careful of third-party strapped cases as the KT has the power switch right where most cases have the upper-right strap.
I had a neopreme slip case from my old Sony 300 that fits the KT well. I do want a bookstyle case though and hopefully someone will start carrying them soon.