I’ve been trying to find information on whether nodejitsu supports PhantomJS or not.
The short answer as of 04/Oct/2013 is NO. 😦
If you try to access phantomjs from your node app, you will find that it is not installed.
If you try to install it using the phantomjs npm module, then you get a 500 error when you try to deploy your app.
However, Modulus.io seem to support PhantomJS according to this article so I’ll give that a go.