https://www.appfog.com/
PaaS offering for a wide range of platforms, free up to 8 servers, 2G of ram, 100M database. Supports, PHP, Node.js and more.
https://www.nodejitsu.com/
PaaS offering for Node.js. Based on units called "drones". Starts at $3/month for a single drone, free for open source projects.
https://github.com/ichikaway/cakephp-mongodb
The CakePHP MongoDB plugin. Include the plugin, create a model, flag it to be sent to Mongo, and boom, your'e in business. Simple, elegant.
http://nuts-and-bolts-of-cakephp.com/2012/07/18/cakephp-mongodb-introduction/
Useful intro to using MongoDB with CakePHP. Works quite nicely, load the plugin, specify your model should use Mongo, and boom, you're in business.
http://apptob.org/
Scripts to auto install node.js on Ubuntu. Includes a few handy dependencies, etc. Neat.
http://www.webpop.com/blog/posts/building-a-scalable-cms-on-the-rackspace-cloud
Interesting article on how webpop built their infrastructure on Rackspace's cloud. Includes links to a few useful tools (chef, wormly, new relic, nagios, ganglia, and others).
http://www.heroku.com/
Ruby, Node.js and Clojure application hosting. Pricing is based on web and background workers. One node free.