- iPhone
- Android
- Samsung Bada
I would like to mention that iphone and Android communities are very much evolved and have a great developer community and resources. Samsung Bada doesnt have a good developer network nor does the SDK support many operating systems. I think it works only on Windows.
You need to first understand the mobile platform architecture, the different frameworks which the platform exposes to the programmers to develop applications.
There are emulators for you to test, however you have to have one of those devices to do a real time on-device testing.
With respect to programming, i think your experience is more than enough but one needs to come out of the frame of mind and think differently. A typical device has limited processing power, limited memory, limited screen space but the user demands beats expectations compared to desktop/enterprise software.
Lastly most important thing is the IDEA of the application. You may want to survey existing application on the stores and start thinking. You can also develop and application which would solve your problem with mobile devices and you know other users also may want such a application.