Amazon announced hadoop support on EC2. Open source is slowly moving to creating a platform to compete with Google AppEngine. There is no doubt in my mind that cloud computing will evolve to new platform.
The two top contenders for dominent cloud operating system are Hadoop and AppEngine. Google AppEngine scales easily and is slowly building out more features and becoming more open source. Hadoop needs more admin features to make the scaling automatic but it has access to the machine level.
Simon Phipps has complained that AppEngine does not support all of the Java API. That is like complaining that planes do not support saddles. It is not possible for AppEngine to support all of the API and still remain fast.
Many Java programmers wanted Java support so Google did the best job it could. The Java folk should just consider it J2Cloud or J2Fast.