On the AIM site, they have a series of steps posted:
"1. Exit AIM
2. From the Start menu, launch "regedit" from the Run dialog box.
3. Browse to the following registry key:HKEY_CURRENT_USER\Software\America Online\AOL Instant Messenger \CurrentVersion\Users\YOUR_SCREEN_NAME\IAmGoneList
4. Left-click once on "IAmGoneList".
5. From the "Registry" pulldown menu, choose the "Export Registry File" menu item.
6. "The Export Registry File" dialog that appears, type the filename that you want to save the file as. Also, make sure that in "the Export range" section of the dialog, in "the Selected branch" option is chosen. 7. Click on Save to finish exporting the registry key.
Double-click on the .REG file that you saved, and the Away messages will be imported into your screen name on the other machine."
Unfortunately, I can't find the "IAmGoneList" from step 3. I get into "My Computer\HKEY_CURRENT_USER\Software\America Online\AIM6\Users\My Screen Name" but I don't see anything resembling "IAmGoneList."