I tried Openshift express verison. It support PHP, Ruby and Python environment. I follow these blog posts:
Two things to mention after using openshift
1. Very quick to deploy your application to cloud, just 3 or 4 commands can work
2, The application source is maintained by git, since git is useful on distributed environment.
user can upload and clone the application source codes just using git
More adventure about openshift is on the way...