Yahoo! Mail beta is around for long time but for only some countries now Yahoo! allow most countries. I was lucky enough to have beta at jun/2006 even i live in somewhere which it is not in the Yahoo International list 
I must tell you that it rocks ,if you are using microsoft’s outlook express and love it you will love this better.
Like the current Yahoo! Mail, the new version is a free, browser-based service, accessible from virtually any computer connected to the Internet, without the need for a software download.
Quote from new Yahoo! mail All your emails, contacts come with you. You can switch back into original Yahoo! Mail anytime.
I won’t go in to more detail since this is just a news story not a service preview 