Users can see each others' databases?

Hi. I'm using PostgreSQL for a database course. Each user has their own
database on the system. Each database is named the same as the user's
user name, and pg_hba.conf is set to require sameuser and a password.

Using pgadmin3 1.2.0 b1 and PostgreSQL 7.4.3 on Fedora Core 2, when a
user connects to their database and browses down the hieararchy, they
can "see" all the other user databases, and browse the list of tables,
etc. They can even see the contents of other user's tables!

Surmising that this was a result of the public schema, I revoked all
rights to public for the public schema in each database. This partly
works in that I'm able to not see the contents of other users' tables,
but I can still get a list of table names, and other information at that
level.

I'm guessing that I'm overlooking something obvious here. What do I need
to do so that users can't see anything from the other users in pgadmin3?
Or, if that's not possible, what can be done to minimize this problem?

Thanks.

Terry