Currently Being ModeratedJul 17, 2012 9:51 AM (in response to rmschwarz)
Settings>Store>Apple ID. Tap the old ID and sign out. Sign in with the new one.
You can also sign in in the App Store and in iTunes. Go to the featured tab in the App Store or the music tap in iTunes, swipe to the bottom of the screen. Your Apple ID is in the lower left corner. Tap the ID and follow the prompts.