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.
http://www.gpmd.co.uk/blog/getting-and-scaling-magento-in-the-cloud/
An article on how to run magento in "the cloud". Includes a split admin / front end severs. Useful.
http://www.zenoss.com/
A cloud monitoring / type service. Partly open source.
http://apphosted.com/
Simplified python hosting in "the cloud".
https://phpfog.com/
PHP cloud hosting. Very slick architecture. Custom managed EC2 nodes deployed behind varnish caches and nginx load balancers. Fairly reasonably priced.
http://www.heroku.com/
Ruby, Node.js and Clojure application hosting. Pricing is based on web and background workers. One node free.
http://kencochrane.net/blog/2011/06/django-hosting-roundup-who-wins/
Article mentioning a selection of django hosting providers that provide "managed hosting". Very useful, some great companies.
http://kencochrane.net/blog/2011/06/django-gunicorn-nginx-supervisord-fabric-centos55/
Useful article on how to deploy django apps on nginx. Handy.
http://uec-images.ubuntu.com/releases/
Handy list of the ami codes to launch an ubuntu server instance on amazon's EC2.
http://www.scalebase.com/
Another cloud based scale solution for MySQL, aims to simplify deploying MySQL "in the cloud".
http://nimbusdb.com/how_it_works.html
Cloud based database that tries to achieve a new type of scalable, highly available, fault tolerant persistent data storage layer in "the cloud".
http://www.enki.co/
Managed cloud computing. A slicehost server for about $50 is roughly equivalent to $113 with enki. Not outrageous for a managed service, depending on how deep the management goes.