Are you sure you aren't just talking about 2 finger scroll rather than kinetic flicking scroll that the iphone uses? If so then you're talking about iscroll2, which I also used on my powerbook pre-leopard, which didn't work after upgrading. The trick is that it now works from the regular keyboard and mouse system pref, but you have to do some fooling around with uninstalling/installing iscroll2 in order to get the 2 finger scroll option to appear in the regular OS X trackpad system pref.
Edit: and oh yeah, are you sure you mean widget? The term widget means something very specific in the computer world, not just any old piece of tech like it means in the non-computer world.