Best way to switch the signed-in iTunes Store account on an iPhone without affecting apps I have an iPhone 4S that uses account "B" for iCloud and account "A" for iTunes.
I also have an iTunes installation (on a Windows 7 machine) that is authorized for account A.
I have many apps installed and configured on the iPhone, several of them cost money.

I now wish to switch over to using only iTunes account B on both the iPhone and the iTunes installation.
What is the smoothest way to do this?

I am worried about several aspects, mainly apps:
What will happen to the apps? Will they be erased? Will they keep their settings?
I am not looking to avoid paying, I am fully prepared to pay (on account B) for the apps that cost money. Should I do that on the PC before switching accounts on the iPhone? 
Do I have to do anything about the free apps? Will all apps keep updating after switching account?

The FAQs I've read about this action state that it is possible, but not really what will happen to apps and settings:
http://support.apple.com/kb/ht1311#
If you switch your iTunes account on the phone from account A to account B all your apps from account A will still exist on your phone and will function properly.

The only issue you will face will be with updates. Every time an update wil exist for one of the apps in account A, you will get the numbered badge on the app store app. However, you will not see the update in the app store itself until you switch accounts back from account B to account A.