The driver class is "org.postgresql.Driver". WARNING: The Postgresql 7.0.2
documentation is out of step with the current JDBC driver in many other
aspects too, e.g., which PreparedStatement and ResultSet methods are
implemented.
I couldn't get the Postgresql JDBC driver registered with the JDBC
DriverManager when I started tomcat with
java -Djdbc.drivers=org.postgresql.Driver ...
I suspect it had something to do with Tomcat's specialised class loader.
The work-around was to change my code to call
Class.forName("org.postgresql.Driver")
which is the traditional way of loading the driver class and registering it
with the DriverManager.