While everyone else is waiting to try the new Yahoo! Mail Beta, people in the UK, Germany and France are already using it.
So, if you want to switch to the new platform and try out the beta version, just do the following changes in your Yahoo! Mail account.
1) Login to your Yahoo! Mail and go to Options.
2) Select the Account Information tab and edit your Member Information.
3) In the Preferred Content filed, choose either Germany, France or UK. If you are to choose UK, it will ask you for a ZIP code — use this UB3 5AJ.
4) Save your changes. Login abck to your Yahoo Mail and you will be greeted with a page which will ask you if you want to try the new Yahoo! Mail Beta.
5) Select Yes and you’re on your way.
{from GoogleOS}