Targeting multiple platform

You can create a proyect and compile a stand alone applications with AIR to Mac, PC, GNU/Linux, iOS and Android

or Can create a web aplication (like Farm Ville) can access this Mac, PC, GNU/Linux and Android

Yes!

When you open Flash select one of the options for each platform.

The main difference when exporting to iOS/Android is you DON'T go to file>Export. You click the spanner icon in the publish settings (properties), then click publish at the bottom.

Charles

Beware the way you code it must stay within the abilities of the devices you wish to code for. Not everything Flash does is supported on every platform. Devices are most limited.

Pre-plan your assets (images/video/audio/etc) in a format suitable for all your targets and keep the quality and resolution as high as possible to start so your desktop version will look and work great. Then be prepared to reduce the quality and have code capable of handling either a new layout/form factor as the screen resolution goes down for devices.

Be prepared to work with some variable hardware. Androids especially have all sorts of different resolution screens and varying hardware support. Just plan plan plan.. Most of your codebase will be re-usable if you continue to think and code like this.

If you're good please mark it answered (correct). good luck!