running vacuum in scripts

This seems like it should be a frequently asked question, but I am having
trouble finding the answer.  I am in the process of switching to using
Postgres, and realize that I need to run vacuum analyze regularly on the
tables.  This is on a Unix system so cron is the obvious choice.  The
problem is I don't want to put the user name and password in the script.
As far as I can tell vacuum must be run by the table or database owner.
It wouldn't be as bad to have the password in the script if it was a
limited permissions user.  Any suggestions on the best methods?

Thanks,
Belinda