How to sync iPhone with multiple iTunes libraries?

Wondering about the same thing (well almost -I have two separate libraries connected to the same computer, switching between them by holding down ALT while starting up iTunes which brings up a dialog asking which library I want to use) I'm surprised nobody has commented on your post yet.

I was hoping you could set one of the libraries to automatically sync while the other would only allow manual transfers, however it seems these settings are with iTunes itself, thereby causing a conflict. Solutions?

 

Are both libraries on the same account? I understand they're on different computers, but if they're on the same account you can share your libraries then import what you don't have and want to synch onto your iPhone.