Comparing database schema's

How are people doing automated comparisons of schemas in different databases?

E.g. we have a dev database, a beta database, and a production database. We
need to insure that changes in schema are propagated properly during the
development and deployment process.

I've experimented some with 'pg_dump -s' to do this: Do a schema dump on the two
databases and a diff. But due to myriad small differences (order of creation
of tables, constraints, etc.) it is very difficult to get a usable diff without
engaging in massive massage of the dump output, including dumping a table at a time.

I found a reference to a schema comparison tool in the mailing list archives, but
it appears to be far out of date and not currently supported.

Regards,

Frank