Open Source Tools: Database Versioning & Change Control

[Java] http://www.liquibase.org/
[Java] http://code.google.com/p/c5-db-migration/
[Java] http://migrate4j.sourceforge.net/
[Ruby] http://wiki.rubyonrails.com/rails/pages/ActiveRecordMigration
[Ruby] http://dizzy.co.uk/ruby_on_rails/cheatsheets/rails-migrations
[Ruby] http://dizzy.co.uk/ruby_on_rails/contents/auto-migrations
[Python] http://code.google.com/p/sqlalchemy-migrate/

Microsoft SQL Server to MySQL:
http://www.ispirer.com/products/mysql-migration
http://www.convert-in.com/acc2sql.htm
http://www.recoverybull.com/recoverybull/mssql-mysql-db.html
http://www.activedbsoft.com/overview-migrate-mysql.html
http://www.spectralcore.com/fullconvert/tutorials/convert-to-mysql.php

Microsoft Access to MySQL:
http://www.convert-in.com/mss2sql.htm
http://www.recoverybull.com/recoverybull/msaccess-mysql-db.html
http://www.activedbsoft.com/overview-migrate-mysql.html
http://www.spectralcore.com/fullconvert/tutorials/convert-to-mysql.php

Oracle to MySQL:
http://www.ispirer.com/products/mysql-migration
http://www.convert-in.com/ora2sql.htm

Sybase to MySQL:
http://www.ispirer.com/products/mysql-migration

DB2 to MySQL:
http://www.ispirer.com/products/mysql-migration

Informix to MySQL:
http://www.ispirer.com/products/mysql-migration