Schema diffs

Hello.

I run a database on two separate servers, one development/test server
and one production server.

The production database is updated quite often, and the development
database is naturally used to quality test changes before deployment.
For small changes manual updates are no problem. For major updates it
has proven to be cumbersome.

I have searched the webb with google for some time now in search of a
usable diff tool for the database schemas. So far the only free tool I
have been able to locate is part of the much larger system ez publish.
It seems like a major overkill for my needs.

Is there any available, preferably free tool that can be used to make
diffs usable to update a production database in parallel of a
development database as I have described?

best regards
Fredrik Olsson