My mom just got a new 12" PowerBook, and I'm helping her move into the world of OS X. When I installed AOL on her new machine, I noticed that her address book didn't transfer over to her new computer automatically. This is because AOL stores your address book on your hard drive, and isn't smart enough to tell that you are on a different computer and might like your data.
Luckily, I figured out how to manually transfer her address book etc. pretty easily. Quit AOL on both computers. If you are on a network, mount the old computer's hard drive. If it is an OS 9 machine, go to System Folder -> Preferences -> America Online -> Data and copy the file Address Book onto your desktop. Rename the file [screen_name]'s Contacts (replace [screen_name] with your screen name, obviously) and drop it in the folder /Users -> Shared -> America Online. Launch AOL and you are all set.
This should also work with the Filing Cabinet file.
Mac OS X Hints
http://hints.macworld.com/article.php?story=2003030319384410