Best way of using web services on iOS?

I'd like to build an iOS app which lets you log in to a web service.

After that, the app would (when the user chooses) send the login name/pass, together with the requested variable(s), over https. For instance开发者_JAVA百科 after requesting 'news-update', it would receive the requested info in XML format... something like:

<news-update>
  <title>Kim Jong-un Promoted</title>
  <story>North Korean leader Kim Jong-il's youngest son, Kim Jong-un, has been appointed a general, amid rumours he is being anointed as successor...</story>
</news-update>

What APIs and techniques should I use for these kind of tasks? I don't want to use any UIWebViews, but instead use standard UI elements.

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What @Ole said, except instead use ASIHTTPRequest to send and receive data over the network.

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NSURLConnection to send and receive data over the network and NSXMLParser to parse it.

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RestKit provides excellent support for quick and easy RESTful requests: http://restkit.org/