how to allow a sysid to be a superuser?

Hi:

PG 8.3.4 on Linux.

A DB was created with a privileged account which has limited access.  I want a specific user (sysuid) to have “all” provs on this DB.  In fact, I want this user to have “all”  on all the dbs served by the PG instance.  Is there a way to do this such that when psql is invoked in a session of that user, he/she automatically has “all” (wothoug havng to enter “-user theuid”)?

Thanks

-dave