Itunes: keeping library/playlists when only some files moved?

[cutcopypaste]

lost a hard drive unfortunately so many of my itunes files are now not found, with the big ole grey exclamation mark. i had the music i cared about on my ipod, and recovered that, but now if i just import that into my library i will have doubles and my many valuable playlists will cease to work. I don't want to go through and relocate 4000 odd files and am wondering if there is some way to get iTunes to automatically detect the new locations? recall reading that somewhere...