http://en.wikipedia.org/wiki/Representational_State_Transfer...
Applying this to one of Vambenepe's examples of an AWS method--
"AWS mostly uses RPC over HTTP. You send HTTP GET requests, with instructions like ?Action=CreateKeyPair added in the URL..."
you can see that it's not RESTful. A RESTful version of this method would have something like "KeyPairs" in the URL path rather than in the query string, and it would use POST rather than GET to signify a create operation.