If you want to host you webapp somewhere and test/present it for free, you can use the free service given by Heroku or Openshift by Red Hat.
Heroku – www.heroku.com – is a good place to get a free web host. It supports most of the web programming languages like Ruby, Node.js, Clojure, Java, Python, and Scala. If you need database you get a 5 MB database for free.
You just need to push your app to your server via git to deploy it.