[quorr]

I'd recommend to watch the sales videos of AWS (http://aws.amazon.com/) they give you a non technical view about what a cloud is.

After that you have a good clue about what the cloud can be and then you can dig deeper into the topics that you what to learn.

Unfortunately I don't know a site that teaches a practical way to cloud computing. They are always tending to a product. But if you understand the basics it should be easy to compare different providers by your needs.