XML : Developing an app that pulls content from a website

I have created a website for an app; An admin will sign into the website and will post a news article using the status update feature on the website. The news will be then be displayed on to the iOS and Android app.

The website is built using Php and MySQL.

My question:

Q1) How do I create a status update feature which posts news to the App. Should I use Php to generate XML?

Q2) How would you do it?

Thanks.