connection pooling for postgres

Greetings,

Sorry for the elementary question but I am still relatively new to Java
and JDBC.

I have 4 clients running on different servers that connect to a Postgres
database, pull down some data, process this data and then insert it back
to the database into different tables.

Because several of the client servers are running on multiple CPUs, or
at least dual core, systems there are actually 10 threads on each client
that are doing the processing. This means 10 connections per server. I
think this is causing some resource problems and would like to see how
things run if I set up a connection pool for each client, of say 3
connections, and the processing threads would then use one of those 3
when it becomes available.

Where can I find good instructions or a tutorial on how to do connection
pooling for JDBC to a Postgres database on my client?

Is there a better way for me to approach this?

Thanks in advance,
James