by mrmacfixit - 9/21/10 9:08 AM
In Reply to: Migrating iTunes Libraries from 2 drives = no joy. by Phil Watkins
Theoretically it should be possible to drag the entire iTunes folder from HD2 into the new iMac, replacing the existing iTunes folder. (the one that came with the new iMac)
From there you should be able to go to iTunes Preferences and tell iTunes where the library is kept.
You could also start iTunes while holding down the option key. iTunes will then ask for the location of a library. Point it at the newly replaced library.