Learn to integrate your SQl developer with open source version with Oracle Sql developer
Use the powerful GUI to browse your database objects, run SQL statements and scripts, and create, edit, debug, and test PL/SQL code in a highly productive environment with new book from Oracle SQl developer 2.1

Advanced Replication
Advanced replication allows the simultaneous transfer of data between two or more Master Sites. Each Master Site is fully functional and doesn't depend on pulling updates from a central site. The example below is a modified version of that found at Underground FAQs. In this example replication is setup between two Master Sites, TSH1 and TSH2, with the TSH1 instance as the Master Definition site, making it responsible for the coordination of the replication process.