I have several URLs I purchased through Dreamhost. I'm starting to use Amazon's AWS, and I'd like to map the URLs to Amazon.

This is something of a silly question, and I've already done the same thing several times to other services (mapping from Dreamhost to WebFaction). But for some reason when I tried to find the proper way to do the same mapping to Amazon, I find a lot of detailed writing talking about whether I should be using CNAME or A records, etc.

So I wanted to ask in the simplest possible terms and hopefully get a simple, concrete answer: I bought a URL from Dreamhost, I have an EC2 server running on AWS (to which I already mapped an Elastic IP address). How do I make the URL map to AWS? And if there are several options, which one should I effectively be using?

P.S. Meta-question - why are things so much more difficult with AWS? When I search Google for "Move from Dreamhost to WebFaction, I get very simple answers on how to do the mapping. In what way is AWS different?