Okay now this is annoying me, I'm in the UK so obviously I need to be on the UK store if I wanna buy stuff. I bought Toki Tori from the UK store on iTunes, however it kept freezing upon completion of the download. I decided I'd download it on my iPod instead, so I synced the device (making sure iTunes was on the UK account), but the iPod app store remains on US. Any ideas?
Or from the App Store app itself, go to "Top 25" or "Categories" or "Featured" tab and scroll to the bottom. You should see a button with your iTunes account. Click that to sign out / sign in.