Importing Addresses from Excel.

Address Book's Import menu includes import from a text file.

What version of OS X is installed on the iMac? Can you install the same version as on the PB?

Unfortunately, I don't have an active Panther installation to check what import alternatives are available for Address Book, but it seems to me that importing a text file has always been an alternative. Check in the /Library/Scripts/ folder for a folder, Address Book Scripts.

I would not try using your PB installer disc on your iMac. If you have a retail copy of Tiger you can use it. And, yes, installing on more than one CPU at a time would violate the license agreement.

You can not import from the Tiger version of Mail because the database structure is not compatible with the Panther version of Mail.

I do have a working Panther installation and the same version of Address Book as Julio, though I don't use it and know nothing about it. On opening the application and choosing Import from the File menu, I have only two options: "vCards" and "LDIF". I have no idea whether saving an Excel file as a tab- or comma-delimited text file (which is easy) would make it possible to convert the entries in it to vCard or LDIF format using some third-party utility. If so, that intermediate step might enable Address Book to import the data. If not, then I suspect AB 3.1.2 isn't going to be able to import the Excel data.

There is an "Import Helper" script in my Library/Scripts/Address Book Scripts/Helper Scripts folder, but I know even less about AppleScript than I do about Address Book, and I can't tell from the negligible information provided about that script exactly what its function is, or what problem it's designed to help with. Sorry...

It is designed specifically to provide additional import options including tab delimited files.