Sync Yahoo! Contacts with Mac Leopard Address Book

I found it interesting that Yahoo!'s Mac Address Book sync instructions states it only works with Leopard (Mac OS X 10.5).

How can I sync my Yahoo! contacts to the Mac address book?

There doesn't seem to be any Yahoo! recommended way of syncing iCal though. A few blogs point to instructions to use a phone as an intermediary point between iCal and Yahoo! Calendar. However, my phone isn't supported by iSync. So, I'm out of luck there.