Microsoft Azure - Windows Azure and SQL Azure enable you to build, host and scale applications in Microsoft datacenters.
Google App Engine - A powerful platform to build web and mobile apps that scale automatically.
Scaleway - Scaleway is the world's first Cloud Computing IaaS platform that offers ARM BareMetal SSD servers, starting at €0.006 on an hourly basis.
Heroku - Agile deployment platform for Ruby, Node.js, Clojure, Java, Python, and Scala. Setup takes only minutes and deploys are instant through git. Leave tedious server maintenance to Heroku and focus on your code.
MacStadium - MacStadium offer Mac colocation and dedicated server rentals plus VMware Mac Pro private cloud environments for large-scale iOS app
Salesforce Platform - Salesforce Platform is a comprehensive PaaS solution that paves the way for the developers to test, build, and mitigate the issues in the cloud application before the final deployment.