pg_dump backup problems with password authentication

Hi all,

I am using PostgreSQL 7.0.2 in RedHat Linux 6.2

I have changed the default authentication, in the pg_hba.conf
file, from trust to password.

Unfortunately, this is giving me problems with pg_dump

I am trying to do a copy of just one database (with all its
tables, primary and foreign keys, check clauses, triggers, etc).

So, I followed the instructions at:
http://postgresql.rmplc.co.uk/users-lounge/docs/7.0/admin/manage-ag1655.htm

and did a pg_dump dbname > dbname.pgdump
(I replaced dbname by my database name, obviously)

Because I have password authentication set, I get an
error message:

Connection to database 'dbname' failed.
fe_sendauth: no password supplied

So, I did a man pg_dump and found out that -u would prompt
for username and password, and -v would give a verbose output.
And so I did:
pg_dump -u -v dbname > dbname.pgdump

The problem is when I press the ENTER key on that command:
it just sits there! Eventually, I have to hit CTRL+C to get out.

Can any kind soul explain me what I am doing wrong? :(

Thanks in advance,
Ricardo Dias Marques
ricmarques(at)spamcop(dot)net