Atk from April 16th did not work for me
The one below worked for me:

To get this working with Yahoo mail, I had to change the following (not sure if it's just me):

original:
var theElement = "http://" + yahooServer + ".mail.yahoo.com/ym/Compose?To="; var begin; var subLength;

modified:
var theElement = "http://" + yahooServer + ".mail.yahoo.com/mc/compose?to="; var begin; var subLength;

As of Sept 8th, I tried it today.....and this is AWESOME!!!!!
I will recommend everywhere.
Thanks