See: http://rubyforge.org/forum/forum.php?thread_id=49102&forum_id=1078

timeoffset_patch.dif

Index: ext/oci8/ocidatetime.c
===================================================================
--- ext/oci8/ocidatetime.c	(revision 411)
+++ ext/oci8/ocidatetime.c	(working copy)
@@ -102,7 +102,7 @@
 
 #if defined RUNTIME_API_CHECK || ORACLE_CLIENT_VERSION >= ORAVER_9_0
 
-VALUE oci8_make_ocitimestamp(OCIDateTime *dttm)
+VALUE oci8_make_ocitimestamp(OCIDateTime *dttm, void *hndl)
 {
     sb2 year;
     ub1 month;
@@ -118,7 +118,15 @@
 
     oci_lc(OCIDateTimeGetDate(oci8_envhp, oci8_errhp, dttm, &year, &month, &day));
     oci_lc(OCIDateTimeGetTime(oci8_envhp, oci8_errhp, dttm, &hour, &minute, &sec, &fsec));
-    rv = OCIDateTimeGetTimeZoneOffset(oci8_envhp, oci8_errhp, dttm, &tz_hour, &tz_minute);
+    rv = OCIDateTimeGetTimeZoneOffset(hndl, oci8_errhp, dttm, &tz_hour, &tz_minute);
+    if (rv != OCI_SUCCESS) {
+        /* Get time zone of the specified handle. */
+        OCIDateTime *sys_date;
+        oci_lc(OCIDescriptorAlloc(oci8_envhp, (dvoid*)&sys_date, OCI_DTYPE_TIMESTAMP_TZ, 0, 0));
+        oci_lc(OCIDateTimeSysTimeStamp(hndl, oci8_errhp, sys_date));
+        rv = OCIDateTimeGetTimeZoneOffset(hndl, oci8_errhp, sys_date, &tz_hour, &tz_minute);
+        OCIDescriptorFree(sys_date, OCI_DTYPE_TIMESTAMP_TZ);
+    }
     have_tz = (rv == OCI_SUCCESS);
     return rb_ary_new3(9,
                        INT2FIX(year),
@@ -239,7 +247,10 @@
 
 static VALUE bind_ocitimestamp_get(oci8_bind_t *obind, void *data, void *null_struct)
 {
-    return oci8_make_ocitimestamp(*(OCIDateTime **)data);
+    oci8_base_t *hndl;
+    for (hndl = obind->base.parent; hndl->type == OCI_HTYPE_STMT; hndl = hndl->parent) {
+    }
+    return oci8_make_ocitimestamp(*(OCIDateTime **)data, TO_SESSION(hndl->self));
 }
 
 static void bind_ocitimestamp_set(oci8_bind_t *obind, void *data, void **null_structp, VALUE val)