I am having enormous trouble finding information on how to migrate my old phone log (with 4500 names and addresses) from Filemaker Pro 5.5 into my Mac address book. Anyone have any peachy ideas on a plug-in or anything that might work?

Can you updgrade? Because why are you asking about plug-ins if you're use FileMaker 5?

Productive Computing has an Address Book plug-in. I imagine it is fast and full-featured. It is designed for synchronization between FileMaker and Address Book.

If you just need to get your them into AB, you could try a text export from FileMaker (Merge). Address Book has a pretty good Import, Text file, which lets you match up the data. I think that would be the way to go.

It is a little bit stupid about Merge files however, which would be my preference for export. It will not recognize it if it is ".mer", but is perfectly happy if you change that to ".csv", and also gives you the option to "skip the 1st record" (which have the field names in a Merge export).

Then there is also AppleScript, which can move all the data, including the Group, if you've got it. It would likely be much slower than a text import however.

You should definitely back up your Address Book data file before you do this. It's in your Home folder, Library, Application Support, AddressBook, AddressBook.data