I'm focusing on an apple iphone application that will fetch data (images + text) from an Content management systems. I'd phone wordpress content management systems. However the application is subscription based. How must i start authenticating the customers that are being forwarded to the content management systems?

Can anybody guide me?

Thanks

Your real question is a little vague, and broad, possibly should you broke it lower a little.

Are you currently utilizing an apple iphone application, or perhaps a standard page having a Mobil browser?

Whether it's an stand alone application are you currently getting problems setting it up to speak to your server/Content management systems?

You getting problems authenticating https versus http?

In case your getting issues with your content management systems or are you currently after content management systems to begin with?

In the seem from it Drupal could fully trust the help module and most likely Ubercart to handle subscription. With zen (base theme) plus some modifications** you may make it Mobil friendly.

http://drupal.org/start

http://drupal.org/project/services

http://drupal.org/project/ubercart

http://drupal.org/project/zen

** http://drupal.org/node/1008582