Adding music to an iphone from multiple computers My iPhone is currently managed on my macbook, where I've added my music library from iTunes onto the phone.  However, I want to also be able to add music from my PC to the iPhone, without erasing the rest of my music. Whenever I try to do this, it threatens to delete the rest of my library. 

How do I add music from multiple computers?
It seems that iTunes Home Sharing would fit the bill for what you're trying to do. Here's the link for the basic requirements. I've done this before myself to consolidate my music library from several different machines. Since you own both machines, you should have no problem sharing your library from your PC to your Mac, and then just syncing from your Mac. However, both machines are required to be using the same local network.