It does. But I found that when I made changes in AB on my MacBook, the changes get synced perfectly. But if I change something in the Contacts app on N900, and then sync with AB, the address entry in AB gets messed up. AB creates a new entry for the address and puts street, city, state and zip code all together in the street field.
For the time being I only make changes in AB, but not on N900. Hopefully it gets fixed soon or Nokia releases the official iSync plugin.