will do this for you.
CopyGear for OS X is one of them.
If you Google for "transfer music from ipod to mac" you will get numberous hits for software that will do this.
Just to satisfy my curiosity, how did you backup your iTunes to the external drive and then bring it back again?
P
Hey
I have just purchased an 80gig Apple iPod Video and I am very satisfied it. After uploading all of my music onto my iPod I decided it would a good measure to backup all that music to my external hard-drive. I did so without problem and from they?re on, I went on the clean my computer's hard-drive, I then accidentally deleted my entire music library
As I proceeded to upload all my music from the external hard-drive, I discovered that the upload was not very successful and created 6 gigs worth of duplicate songs, but more importantly, the upload failed to upload the entire music library, it uploaded most of it, but some albums and artists were missing. Before trying to re-piece my library, I tried to find a way to upload the music from my iPod to my computer. I am not familiar with how to do this procedure.
Any help or ideas on how to solve my problem would be greatly appreciated!

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