Q: Help with itunes Library

Hi

I recently had to buy a new MacBook Pro as the logic board on the old one died.  I've managed to migrate most of the apps and docs via a firewire connection and a target disk mode boot.

However, I'm wondering what on earth do do about itunes and iphoto content... much of which was actually stored on another external hard drive (still working) which the old mac pointed to.. although there was some content on the local drive.

I have pointed the new mac at the external hard drive library and sure enough if I play anything from that drive it works.  However, the content doesn't show up automatically in the music window on the new mac so short of going through every song and playing it from the external hard drive, I can't recall / see what's on there. 

Any advice on how best to deal with it welcome.   

Thanks