I've had an Apple ID for a while now and have many iTunes purchases associated with the account. Yesterday, I created a MobileMe account. I tried updating the existing Apple ID account e-mail with my new MobileMe address, but get an error about the MobileMe address already being associated with an iTunes account (I'm guessing it's automatically created when you create a MobileMe account). Is there a way to update my existing Apple ID to use my new MobileMe address so that I don't have to repurchase all of the apps and things I've downloaded on my original account?
You can call AppleCare as suggested and merge all your purchases from the old Apple Id to the new Apple Id.
I have multiple Apple IDs. Is there a way for me to consolidate them into a single Apple ID? Sorry, but this is not possible at this time via our online tools. You can speak with an AppleCare representative, who can help you consolidate your registered Apple products. They can also help register your iPods, iPhones, or Mac computers under a single Apple ID.
Other links that could offer some insight:
As I have attempted to do this myself, Im pretty sure you cant combine the two. You can try contacting Apple Support but they will probably tell you the same thing.
Apple doesn't allow you merge AppleIDs or in other words use a mobileme AppleID for an iTunes account AppleID ( AppleIDs are just the username/email address I think). This sounds reasonable though because mobileme is a yearly paid service and in the instance you canceled the mobileme account, it might lead to account problems (ie if you needed to reset your password for your iTunes account but it still had the mobileme email address as the AppleID/email)
You should still be able to make iTunes purchases, app purchases, etc with the original iTunes account you had set up.
Log onto your newer MobileMe account and change the email address to something else, say one of your temporary email addresses. Wait a bit. Then change your old account to use the MobileMe email address.
I doubt that it is possible to merge a mobile me account with your apple id, but try contacting the support - I think they are the ones to know for sure. See http://www.apple.com/support/itunes/ -> Authorization -> Troubleshooting -> "Email Us".