BRETT JOLLY  I purchased Bento 2 (family pack 5 licences) as an afterthought whilst on holiday in the Uk, I work on a very international basis and therefore have many contacts in my address book; so I loaded the app. on my powerbook pro and spent 2 day tidying up my contacts after importing them from address book to Bento. Upon getting back home put into my new iMac 24" (using another licence key). Then my world fell apart. I had paid £58.00 for an application that came with another 4 days of trying to get Address book and iCal to sync over Mobileme. My iPhone, my iMac and my Powerbook all THOUGHT they were syncing and went through the motions as they normally do, BUT empty address books everywhere, and nothing on the cloud. BUT I did solve it, here's what you do....

Export your address book as a group vcard onto your desktop, delete all contacts in your address book, Delete Bento completely, go to spotlight and remove every file that uses the word Bento, then delete:

library/application support/address book/ addressbook-v22.abcddb

library/preferences/com.apple.addressbook.plist

then re-import the group vcard into address book.

the take the Bento CD a tin of lighter fuel and a match..... well you get the idea.  
(Version 2.0v2)