I created a new User Account in Leopard 10.5.6. This is so that I could sync my other phone with a new Address Book. However, when I logged in as this new user, the Address Book contains my old data in my Admin account. Is there a way to create a clean slate for everything? I also do not like the idea that another user can access my data.
That's weird, a brand-new account shouldn't have any user information at all. Try deleting the newly created account and create another user account (make sure you choose a new account short name too).