I once sent a letter to Steve Jobs saying that the MacOS (and other operating systems) were susceptible to phishing by applications, which would simply present a dialog that looks very much like the System Security dialog, and thereby gain the user's root password.

The solution is to have an area where only the operating system can draw (and which cannot be screen-captured, the same way Apple currently does with DRM movies). In this area, the system would present to the user a phrase which the user selected when setting up their account.

This would prevent phishing, as users would be trained to look for the phrase (and / or icon ... the reason you can't have an icon alone is because the phisher could get it right 1 out of N times).

Now, on the web there is a similar thing you can do! When someone places KEYBOARD FOCUS in your password box, and starts typing the correct password, you display the icon + phrase that you previously selected when setting up your account. If the phrase doesn't pop up or is different, you know you're being phished.

THIS is a great way to stop phishing on the web. Anyone impersonating you will not know what phrase to display. Only by starting to type the correct pass phrase will they get this information. On the other hand, they won't be able to place anything fake over the password input box and capture your input, because the phrase only appears when you type IN the password input box, which the attacker can't get to, thanks to the cross-domain security in browsers!