Wow, South sounds pretty awesome! I'm not sure of anything out-of-the-box that will help you nearly as much as that does, however if you choose Hibernate as your ORM solution you can build your own incremental data migration suite without a lot of trouble.
Here was the approach that I used in my own project, it worked fairly well for me for over a couple of years and several updates/schema changes:
Maintain a schema_version table in the database that simply defines a number that represents the version of your database schema. This table can be handled outside of the scope of Hibernate if you wish.
Maintain the "current" version number for your schema inside your code.
When the version number in code is newer than what's the database, you can use Hibernate's SchemaUpdate utility which will detect any schema additions (NOTE, just additions) such as new tables, columns, and constraints.
Finally I maintained a "script" if you will of migration steps that were more than just schema changes that were identified by which schema version number they were required for. For instance new columns needed default values applied or something of that nature.
This may sounds like a lot of work, especially when coming from an environment that took care of a lot of it for you, but you can get a setup like this rolling pretty quickly with Hibernate and it is pretty easy to add onto as you go on. I never ended up making any changes to my incremental update framework over that time except to add new migration tasks.
Hopefully someone will come along with a good answer for a more "hands-off" approach, but I thought I'd share an approach that worked pretty well for me.
Good luck to you!