Connection Pooling for PHP based website using Oracle 11g database
where would I be setting the number of connections?


You can specify the min and max number of connections in the pool using

SQL&gt;execute dbms_connection_pool.configure_pool(null, minsize=&gt;10, maxsize=&gt;100);





  If the database servers are unix boxes, can we do any ODBC connection pooling?


I'm not quite sure why you're asking this.  You can take advantage of DRCP via OCI in PHP, as long as you have the Oracle 11g client.  Just specify your connection string like myhost.dom.com:1521/sales:POOLED and make your connections using oci_pconnect().



Here's a few resources that may be of help:


Oracle DRCP Whitepaper
DRCP entry on OraDBPedia
PHP OCI manual