Upgrading postgresql -- how to dump databases?

[Debian User <brian@nadasutra.net>]

Okay... so I've upgraded from stable to unstable, and everything seems to be
working fine... except postgresql.  When upgrading, I got a message telling
me to dump my databases and convert them to the new format.  Since I didn't
have any databases at the time, I didn't think much of it.  Now, however,
when I try to start postmaster, it says it can't find the data directory.
Are there databases that I'm missing?  Did it even get upgraded?

Thanks,
Brian DunnettE