Grant on table without access to other tables structure

Hi,

  I will explain what I need with a simple example.

  I have three tables:
     jobs, people, cities

  I have to grant select on people to john.

    GRANT SELECT ON PEOPLE TO JOHN;

  Now, when john opens "psql", it can do the selects. That is OK.

  But when john does
    \d
    \d cities

  He can see the other table names and structures...

  How can I revoke this rights?

  How can I create a new user and give him select rights on some tables,
but not disclosure the full database tables and fields?

  PG is 8.3

  Thanks,
  Pedro