I'am new on the Amazon Cloud World, and i trying hard to understand how this hosting works. I can't found any articles about buckets. What is buckets, anyway? Someone know a good article/book about the Amazon EC2?
EC2 doesn't have buckets. S3 does, though. S3 is AWS's bulk object stoage solution, and buckets are the top-level organizational structure under which S3 objects are stored. Think of them as folders, but with the caveat that you can't have nested buckets.
As far as reference material goes, the wikipedia articles on the various AWS services give pretty good overviews:
For more detailed information, check out the AWS developer docs.