I have a Wordpress blog that displays scientific news.
I need to create an iPhone app, news reader that reads from the same MySQL database online of the website. Any ideas if I can find a tutorial that can help?
Wordpress has an XML-RPC and AtomPub web api. That would allow you to make http calls from iOS using NSURLConnection or another http api. For that you would use NSXMLParser on the iOS side.
If you need to query your data out of a MySQL database, then I would strongly recommend putting an http web api on top of it using something like ASP.net web api, PHP, node.js etc...
The http server could return json as the data and in iOS 5 and beyond, there's a JSON parser: http://www.raywenderlich.com/5492/working-with-json-in-ios-5