I'm not 100% sure, but I would imagine that you don't need to do anything special to
deal with touchscreen technology. I think the pointing device, which is usually a mouse, just becomes a touch
but you deal with the typical events in ActionScript.
A quick Google search found this: http://blog.six4rty.ch/2008/09/23/flexflash-based-touchscreen-applications/ which seems to confirm my statement above and may get your pointed in the right direction. One of the commenters even posted a link to a 360Flex presentation that might help you.
In addition, here's an article on the Adobe Developer Connection by Christian Cantrell on some of the ActionScript APIs available to you for multi-touch and gestures. These ActionScript APIs are available in Flash Player and AIR betas, so you can get a head start:
Christian's blog is also a great resource:http://blogs.adobe.com/cantrell/ .
Hope this help,