What you would do is on computer authorize other account for that computer. So you computer is authorized to play both accounts. Then you can sync apps from both accounts to your phone using the same computer as before.
My wife and I both have our own accounts and each of our instances of iTunes have authorized each others accounts for that computer. So I can sync her apps and she can sync mine. Just becomes a pain when you update an app via the cell phone when updates come out as trying to do all at once usually fails if the apps for updating are for each account. So have to do one at a time or just have them update via iTunes and sync.
bab2010 said:You can gift apps from one account to another account, if the app is not for free, the account gifting the app will have to pay it and then gift it to the second account. That's the only way i know you can transfer apps from one account to another account.