My wife and I each have an iTunes account. We just got a new iMac, and we want to merge our accounts into the main machine and use them together on our iPhones and ipad2.

Question

My wife and I each have an itunes account. We just got a new imac, and want to put all of our media on it. Can we share songs and media from two diffrent accounts on the imac, our iphones, and the ipad2?

Answer 1

Decide which device will be changing accounts.  On that device, if you have any photos in photo stream that are not in your camera roll that you want to keep on the device, save them to the camera roll by opening the photo stream album in the thumbnail view, tapping Edit, then tap all the photos you want to save, tap Share and tap Save to Camera Roll. 
Once this is done, go to Settings>iCloud, scroll to the bottom and tap Delete Account.  (This will only delete the account from this phone, not from iCloud.  The device(s) that will be keeping the account will not be effected by this.)  When prompted about what to do with the iCloud data, be sure to select Keep On My iDevice.  Next, set up a new iCloud account using a different Apple ID (if you don't have one, tap Get a Free Apple ID at the bottom).  Then turn iCloud data syncing back to On, and when prompted about merging with iCloud, choose Merge.  This will upload the data to the new account.
Finally, to delete any data that you don't want in each account (such as deleting your wife's data from your account, and vice versa) you will have to go to icloud.com on your computer and sign into each iCloud account separately and manually delete it.