Q:

How can my Perl script use Amazon clouds? 

I want my Perl script can handle a large number of users. 
I'm going to run the script on Amazon clouds servers. 
This is my understanding of how the clouds work. 
At first the script instances are run on a single server. 
Then at the moment the server gets overloaded by too many users, the second server is added to run script instances. 
Do I understand clouds right? 
Do I have to do anything special to make this process work? 
Or maybe everything is run seamlessly and the only thing I have to do is to upload the script to the image? 

A:

That is a bit too narrow of a definition for cloud computing but probably close enough for the purposes of this question.   The process isn't seamless, you have to actually detect that you're running too hot for the singe machine and add another instance.   You can do this from perl using the API.  It does, however, take real time to spin up another instance so it makes more sense to distribute your task initially.   
If your perl script is something which can cleanly run in parallel already then you don't have to make many changes.   Just shove it onto a number of instances and away you go. 