Aloha TimJim,
I won't have that issue, due to my particular setup. Here's what I do. I have an external HDD on which I have both my iPhoto and iTunes libraries. This serves two purposes: I can use either my iMac or MacBook Pro for either of those programs and all changes will reflected on both computers, and it is backed up such that in case something disastrous happens to either computer, the data is still available.
If you have a spare HDD lying around (with enough space), you can easily pick up an external case for it, then move your iTunes library over to the new drive. That way, when you do a clean install of Leopard, you won't have to worry about your music files, as they won't be on your Mac's drive.
HawaiiMacAddict