Yes, there is Oracle SQL Developer, which is maintained by Oracle.
Oracle SQL Developer is a free
graphical tool for database
development. With SQL Developer, you
can browse database objects, run SQL
statements and SQL scripts, and edit
and debug PL/SQL statements. You can
also run any number of provided
reports, as well as create and save
your own. SQL Developer enhances
productivity and simplifies your
database development tasks.SQL Developer can connect to any
Oracle Database version 10g and later
and runs on Windows, Linux and Mac
OSX.