The README is in Google's codepreview which uses Google-appengine.
To run the app locally (e.g. for testing), download the Google App Engine SDK from http://code.google.com/appengine/downloads.html. You can then run the server using
make serve
I run make serve in my terminal after moving Google-appengine.app to my Application -folder in OS X Leopard.
I get
make: *** No rule to make target `serve'. Stop.
How can you run the make serve to run the server for Google AppEngine?