Newbie server help

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Please excuse my newbie knowledge.

I have got the basic knowledge of objective-c and would like to know if there are any good reads or tutorials regarding sending data to and receving data from a server in regards to an app.
I'm in the process of creating a blog based app but am getting a little stuck regarding how it sends and receives the data. In fact I need some knowledge of how to even set up the server or is there a way I can use a third party server?