This is intended to be an initial set of resources for those looking at getting started in this exciting area of drupal/mobile app development.
These resources are largely the work of Sumit Kataria of Civic Actions and my interest and excitement stem from this awesome presentation at Drupalcon SF2010 http://sf2010.drupal.org/conference/sessions/developing-apps-iphoneipada...
The presentation is broken down a little further with some provided code samples and an adjusted json server module.
http://civicactions.com/blog/2010/may/02/drupalcon_developing_apps_iphon...
http://civicactions.com/blog/2010/apr/30/drupalcon_developing_apps_iphon...
Then there seems to be some good work being done by Chris Callendar with demonstrating services authentication
http://blog.soniccode.com/php/drupal-connected-iphone-application-using-...
Titanium API is an open source project created by (and available from) http://www.appcelerator.com
It is a framework that allows apps to be written in Javascript and compiled to native apps for i-phone, i-pad and Android with Blackberry support coming soon.
More on getting started is available in their developer area
http://developer.appcelerator.com/ and there are regularly posted examples and tutorial at http://developer.appcelerator.com/blog/
Please feel free to add any additional resources you come across to help make this group a useful place to learn and ask questions about Titanium API and Drupal.