Making Database Connections
June 17, 2008[From OTN]
Connect to Oracle and third-party databases from Oracle SQL Developer.
Oracle SQL Developer enables developers and DBAs to browse, create, and update data in a database. Before you can perform those actions, however, you must create at least one database connectionan Oracle SQL Developer object containing the information needed to connect to a specific database as a specific user.
The article continues at http://www.oracle.com/technology/oramag/oracle/08-may/o38sql.html