Numerical DB/Table Names

I've just recently started working with PostgreSQL.  We have a 7.0
insallation and everything seems to work fine.  I am embarking on
upgrading to 7.1.3 but have run into a problem.  All of the databases
are stored with numerical names in the /$prefix/base directory.  They
seem to be stored as binaries so I am unable to open any files under
that directory.  I know that in our 7.0 version of PostgreSQL all
databases have a directory under the /$prefix/base directory that is
labeled as the name of the database.  Inside each database directory the
physical data is stored in files that have the same name as all the
relationships in the database.  I can still insert and retrieve data
from any database created on this new 7.1.3 cluster but am not
comfortable with not being able to read the data files.
Has anyone encountered this problem?  Thanks in advance for any help you
can provide.

Jeff