Professional PHP developer

Google App Engine suport Python and Django out of the box. On the project page, people started to vote on the next language that will be nice to have supported by next version of the Google App Engine.

Ruby, Perl, Java and Php are on front.

http://code.google.com/p/googleappengine/issues/list?updated=13&ts=1207903607

So, if you have a preference just go and give your feedback, if not, you can allways choose PHP.