Revoking the right to create (non-temporary) tables?

[Brian Hurt <bhurt(at)janestcapital(dot)com>]

Is there a way to revoke the right of a given user from creating 
tables?  By preference I'd restrict only creating non-temporary tables.

I've tried both
REVOKE CREATE ON DATABASE dbase FROM user;
and:
REVOKE CREATE ON SCHEMA public FROM user;

neither of these seem to work.  Help?

The idea I'm looking for is a "safe" user- a user that can view the 
production database but can't change or create anything.  This allows 
fumble-fingered admins to keep a psql open in a window without having to 
worry about typing the wrong command in the wrong window, and also 
allows us to give out "guest" accounts.

Brian