Downloaded jar file won't work

I have downloaded jdbc6.5-1.2.jar from
jdbc.postgresql.org and I can't get it to work with
java. I am running Red Hat 6.2 and PostgreSQL 6.5.3
along with this I am running Tomcat 3.3. I have tried
adding the jar file into the classpath but it doesn't
work. Is there anything that I must do to the jar file
to get it to work? Is this the right file to get?

Ben

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