Alright, here's my situation:
-Computer: iMac, Mac OS X Leopard, iTunes 8.1.1. The current library for this installation of iTunes is located on a secondary hard drive, at: Audio:Music:iTunes:iTunes Music
-External hard drive: Holds the iTunes library for my home computer.
-iPhone: Holds its own downloaded songs and applications. Used to be homed/paired/joined/etc to a PowerBook that has since died.
I'd like to combine all iTunes Music Libraries into one library. I'd like to keep this library on the external drive so that I can use it at home and at work. I'd like the iPhone to be homed at the work iMac. So, how do I combine all of the libraries (I'm okay to lose playlists, but I'd prefer to not)? And, how do I move my iPhone to the iMac without losing any of the applications that I've paid for and downloaded to the iPhone?