Utility computing or the cloud computing is becoming the next generating computing platform, which reduces the time and cost. So when we want the resource we go and rent depending on the time we want and depending on the money we have. According to my understanding Amazon EC2 plays a big role in Cloud computing, and of course they use Web Services for almost everything.
Apart from commercial cloud infrastructure, there is on good open source cloud infrastructure as well, which is called EUCALYPTUS (a research project). I knew about this for a few months, but I did not know that they use Axis2 as the Web Service framework until today (Thanks Deep for letting me know that). One of the cool thing about EUCALYPTUS is that is functionally equal to Amazon EC2. So if you want to do the testing on your system before you move into Amazon EC2, then I think this is a good way of doing that.