How to maintain a schema per user?

[Paul Spencer]

I have an application that requires a logged in user be restricted to a 
schema within the database.  For the sake of illustration, the 
application is an address book and their is one schema per user.  The 
database structure of the table and views within each schema are exactly 
same.

My questions:
1) How do insure that a logged in user will only access the data in 
their schema?

2) How can a new schema be automatically created when user is created?

Paul Spencer