You had better ingore this post, because Google App Engine supports PHP now.
Google App Engine supports Python and Java now, but does not support PHP, but some body offer a hack to Run PHP on the Google App Engine.
He uses Quercus in GAE.
Quercus is Caucho Technology’s fast, open-source, 100% Java implementation of the PHP language (requires JDK 1.5).
For details, please visit,Run PHP on the Google App Engine