I want to sync my iphone 4s to my home computer but have a different account for all the music on my home computer than on my iphone. What do I do?

Question

I just got the Iphone 4s and am attempting to synch it to my home computer for the first time in order to transfer music and such. However, my home computer is set up with a different apple ID linked to my itunes library than my iphone apple ID. How do I transfer music and is it possible to merge accounts?

Answer 1

Apple ID accounts cannot be merged, and you can't transfer purchases to a new ID.  Purchases are permanently tied to the ID used to purchase them.  You can, however, authorize your home computer for another Apple ID by opening iTunes and going to Store>Authorize this computer, and signing in with the other ID.  This will allow you to add purchases from this ID to your iTunes library and sync them with your phone.
When you sync with an iTunes library for the first time iTunes will delete all iTunes media (apps, music, movies, etc.) from your phone and replace it with the media in the iTunes library you are syncing with.  It's important to transfer your content to your new iTunes library prior to syncing so, although it will be deleted, it will simply be transferred back to your phone when you sync.  Music purchased from the iTunes store can be transferred from your phone to your library prior to syncing (as explained in the linked guides below), however music from other sources cannot.  You will either have to add these to iTunes from other sources (such as by ripping your CDs again) or use 3rd party software capable of transferring it from your phone (such as Touch Copy).
Follow these guides to start syncing with your new iTunes library with minimal or no data loss:
Syncing to a "New" Computer or replacing a "crashed" Hard Drive
Recovering your iTunes library from your iPod or iOS device