I went to Chris Jones' workshop this morning at the PHP Quebec conference and picked up a few nice tidbits. The OCI interface supports passing arrays to pl/sql procedures and functions. You just bind the array variable like any other variable. In another example, he was creating XML through a query and the SELECT had an interesting feature:
SELECT field, CURSOR(SELECT bla FROM bla) etc.
It looks like you can retrieve variable array type data in your query. He also demonstrated the performance benefits using oci_set_prefetch().