The HTML 5 drag'n'drop API allows you to implement drag'n'drop with the same code on most desktop browsers. Unfortunately, you'll notice iOS doesn't support it, so no iPad action for you!
Luckily, WebKit gives us enough tools to shim seamlessly. If you drop this script in your page your existing HTML 5 drag'n'drop code should just work.
Check out the demo to see it in action. It should work on Android, but I don't have an Android phone to test. Let me know @timruffles.
touchenter- iOS doesn't fire it, and I can't see a way to shim itmouseovercan't help as because iOS only fires it on press.
@rem - who created the original demo used to demo this shim's drop-in nature.