They have not updated this in 2 years. The interface is clunky, & you have to sync entire categories without being able to restrict it to certain keywords. This would all be forgivable if it worked. But it consistently mashed different contacts together during the transfer, and even pulled contacts from categories I wasn't syncing.
I can only assume they are working with Apple on making Now Contact v5 work seamlessly with Tiger.
My recommendation: don't bother. Unfortunately, I have not found any apps that will let me transfer data between a VCard based program and a spreadsheet based one. Arrgh.