Yes and no. The cache isn't based on your contacts, it's based on what you
type when you send emails. As you enter address in the To: filed the are
remembered. So, you could copy the cache from one machine to another if you
wanted, but you couldn't import it into Contacts. If you want to copy it
from machine to machine, with Outlook closed search your computer for
"outlook.nk2" (sans quotes). It's a hidden file, so make sure you're
searching in hidden/system folders or have show hidden files turned on
depending on your OS. Then copy it over to another machine and put it in
the same location you found it.
