UI Stencils http://www.uistencils.com/ Use these templates and tools for rapid prototypes that are to scale for the device you're building to...
Project management tools like basecamp, assembla http://www.assembla.com/
- Fieldtest - web based tool to create fast mobile prototypes. http://fieldtestapp.com/ (focused on smartphones and up = android, iOS, windows mobile)
Chad shares a prorotype he created that you go checkout: http://fldt.st/10d1c7f
- App cooker http://appcooker.com/ An ipad app for building iphone and ipad apps (very meta) $25...
Once we've got the design prototypes...the tools to build the application:
Chad cannot recommend any of the rapid learning tools for dedicated mobile development.
"Anything that's out there now, is not doing it well. if you want to build high quality mobile learning apps, you have to use dedicated mobile tooling."
HTML, CSS, and learn some basic design for user experiences for mobile.
jQuery mobile http://jquerymobile.com/ It's just like webdesign. Dreamweaver has this stuff built in for the newer versions.
(And Chad exhorts everyone to stop being scared of HTML - it's just an outline -- it's not programming!)
PhoneGap -- http://phonegap.com/ the only open source mobile framework that supports platforms. Helps you bundle up content to an app that's distributable to a marketplace (android, apple, etc.) Adobe purchased phonegap and is building it into all of their tooling.
Misconception that apps have to go through the app store. Apperian...helps you avoid putting proprietary content into the App store. www.apperian.com