Managing Google App Engine SDK versions on OSX with virtualenv
A more manageable way is to not use the GAE launcher, but to download the SDK manually, then set up a virtualenv to use a particular SDK. I also use virtualenvwrapper to help me switch easily between environments.
This is the pertinent bit - in the folder where your virtual envs are stored, add the path to the app engine sdk in bin/postactivate. Postactivate gets run when you activate the virualenv through virtualenvwrapper. E.g for something using version 1.8.8 you might have something like:-
# This hook is run after this virtualenv is activated.