mysqldiff-like utility for PG?

Is there any utility like mysqldiff
(http://adamspiers.org/computing/mysqldiff/) for PG?

"mysqldiff is a Perl script which compares the data structures (i.e.
table definitions) of two MySQL databases, and returns the differences
as a sequence of MySQL commands suitable for piping into mysql which
will transform the structure of the first database to be identical to
that of the second (c.f. diff and patch). Database structures can be
compared whether they are files containing table definitions or
existing databases, local or remote. "

It would make our lives 1000x easier if such a tool existed. As it
stands now, the process of updating the DB involves manually writing a
series of alter statements, which is a huge pain. I can't be the only
one with this problem!

Any and all help is appreciated. Thanks.