Roman Nurik posted some beta code implementing this feature a couple of months ago. Caveat is that it's only compatible for ICS+ devices. Fortunately, Jake Wharton backported the code soon after publication, using the NineOldAndroids library.
- BETA Android 4.0-style "Swipe to Dismiss" sample code
- Backport of Roman Nurik's "Swipe-to-dismiss" sample code using NineOldAndroids to work on all API levels
The latter provides a sample APK too, in case you feel like having a play with the result first.
