I am writing an application which is supposed to work on various mobile devices, and i need to retrieve the device hardware on which it is running.
As Flextras pointed out, check out the documentation for the following classes:
http://help.adobe.com/en_US/FlashPlatform/reference/actionscript/3/flash/system/Capabilities.html
http://help.adobe.com/en_US/FlashPlatform/reference/actionscript/3/flash/sensors/Geolocation.html
http://help.adobe.com/en_US/FlashPlatform/reference/actionscript/3/flash/system/System.html
You may find additional stuff of interest within the flash.system.* package:
http://help.adobe.com/en_US/FlashPlatform/reference/actionscript/3/flash/system/package-detail.html