Christopher Jones has a correction on his blog for a developer guide that Oracle has put out (Oracle Database Express Edition 2 Day Plus PHP Developer Guide 10g Release 2) mentioning a problem in chapter three:

In chapter three "Connecting to the Database" at step 5 of you will get duplicate columns returned if you use the latest version of PHP.

By adding in a "OCI_ASSOC+" to the oci_fetch_array statement, all is corrected. This was due to a change in how oci_fetch_array worked (as seen in this bug).