PostGreSQL - Accessing It

I installed RedHat 9.0 and found that PostGreSql was installed with the OS.  I started the service, tried to create a database.

I cannot access/create a database from root or any of the other accounts I have setup for RH9.  I noticed that there is a user setup for postgres (I guess this part of the postgres install) but can’t login as that user.  I can’t even read or change the password.  How do I get at PostGreSql?

Secondarily – does anyone know if JDBC drivers are part of the RH9 PostGreSql install? 

Thanks in advance.

Michael