Retrieving data from the data files.

For whatever reason, I seem to be plagued with issues...
Whether they're hardware or operating system or a bad
combination....I'm not sure yet....and I find myself needing
to recover from postgres not wanting to play all too often.

In looking at the database data files, I notice that in (for example)
a file called /data/db/base/10819/16397, are the contents for
one of the relations. The data appears to be correctly stored
with NULLs for field seperators, etc. On the assumption that
the raw data itself is ok, how do I get that data out?

Has anyone written a program to extract data directly from
the database data files without using postgres?

Are there any caveats in doing so?

Darren