Currently Being ModeratedApr 22, 2013 9:23 AM (in response to lochinver lady)
go to Appleid.apple.com and log in with the old Apple ID
change primary email address
done, nothing will change, besides the email addres
after you're done: log out of the stores/remove icloud account from your devices and log in with the new emailddress. Your purchases will still be on the account.